Refactor server-side communications (#11192, #7891)

* Move UIDL writing from AbstractCommunicationManager to UidlWriter
* Move request handling from ACM to RequestHandlers
* Move server RPC message handling to ServerRpcHandler
* Move portlet event notifications to PortletListenerNotifier (a RequestHandler)
* Communication handlers reside in c.v.server.communication

Change-Id: I087e923dbdf88c6b3fcaafbdb7f685d9d3dad0c1

35 files changed, 3364 insertions, 2490 deletions

diff --git a/server/src/com/vaadin/server/AbstractCommunicationManager.java b/server/src/com/vaadin/server/AbstractCommunicationManager.java
index 17bbbda737..29dc5b2f81 100644
--- a/server/src/com/vaadin/server/AbstractCommunicationManager.java
+++ b/server/src/com/vaadin/server/AbstractCommunicationManager.java
@@ -16,36 +16,17 @@
 
 package com.vaadin.server;
 
-import java.io.BufferedWriter;
-import java.io.ByteArrayOutputStream;
-import java.io.CharArrayWriter;
 import java.io.IOException;
 import java.io.InputStream;
-import java.io.InputStreamReader;
-import java.io.OutputStream;
-import java.io.OutputStreamWriter;
 import java.io.PrintWriter;
 import java.io.Serializable;
-import java.io.StringWriter;
-import java.lang.reflect.Type;
+import java.io.Writer;
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.security.GeneralSecurityException;
-import java.text.CharacterIterator;
-import java.text.DateFormat;
-import java.text.DateFormatSymbols;
-import java.text.SimpleDateFormat;
-import java.text.StringCharacterIterator;
 import java.util.ArrayList;
-import java.util.Calendar;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.Comparator;
-import java.util.GregorianCalendar;
 import java.util.HashMap;
 import java.util.HashSet;
-import java.util.Iterator;
-import java.util.LinkedList;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
@@ -54,37 +35,19 @@ import java.util.UUID;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
-import javax.servlet.http.HttpServletResponse;
-
-import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;
 
-import com.vaadin.annotations.JavaScript;
-import com.vaadin.annotations.PreserveOnRefresh;
-import com.vaadin.annotations.StyleSheet;
 import com.vaadin.server.ClientConnector.ConnectorErrorEvent;
-import com.vaadin.server.ComponentSizeValidator.InvalidLayout;
-import com.vaadin.server.ServerRpcManager.RpcInvocationException;
-import com.vaadin.server.StreamVariable.StreamingEndEvent;
-import com.vaadin.server.StreamVariable.StreamingErrorEvent;
+import com.vaadin.server.communication.LocaleWriter;
 import com.vaadin.shared.ApplicationConstants;
-import com.vaadin.shared.Connector;
 import com.vaadin.shared.JavaScriptConnectorState;
-import com.vaadin.shared.Version;
-import com.vaadin.shared.communication.LegacyChangeVariablesInvocation;
-import com.vaadin.shared.communication.MethodInvocation;
-import com.vaadin.shared.communication.ServerRpc;
 import com.vaadin.shared.communication.SharedState;
-import com.vaadin.shared.communication.UidlValue;
-import com.vaadin.shared.ui.ui.UIConstants;
 import com.vaadin.ui.Component;
 import com.vaadin.ui.ConnectorTracker;
 import com.vaadin.ui.HasComponents;
-import com.vaadin.ui.LegacyComponent;
 import com.vaadin.ui.SelectiveRenderer;
 import com.vaadin.ui.UI;
-import com.vaadin.ui.Window;
 
 /**
  * This is a common base class for the server-side implementations of the
@@ -100,7 +63,8 @@ import com.vaadin.ui.Window;
 @SuppressWarnings("serial")
 public abstract class AbstractCommunicationManager implements Serializable {
 
-    private static final String DASHDASH = "--";
+    // TODO PUSH move
+    public static final String WRITE_SECURITY_TOKEN_FLAG = "writeSecurityToken";
 
     private static final RequestHandler UNSUPPORTED_BROWSER_HANDLER = new UnsupportedBrowserHandler();
 
@@ -122,47 +86,24 @@ public abstract class AbstractCommunicationManager implements Serializable {
                 String details, String outOfSyncURL) throws IOException;
     }
 
-    static class UploadInterruptedException extends Exception {
-        public UploadInterruptedException() {
-            super("Upload interrupted by other thread");
-        }
-    }
-
-    // flag used in the request to indicate that the security token should be
-    // written to the response
-    private static final String WRITE_SECURITY_TOKEN_FLAG = "writeSecurityToken";
-
-    /* Variable records indexes */
-    public static final char VAR_BURST_SEPARATOR = '\u001d';
-
-    public static final char VAR_ESCAPE_CHARACTER = '\u001b';
-
+    // TODO Refactor (#11410)
     private final HashMap<Integer, ClientCache> uiToClientCache = new HashMap<Integer, ClientCache>();
 
-    private static final int MAX_BUFFER_SIZE = 64 * 1024;
-
-    /* Same as in apache commons file upload library that was previously used. */
-    private static final int MAX_UPLOAD_BUFFER_SIZE = 4 * 1024;
-
     /**
      * The session this communication manager is used for
      */
     private final VaadinSession session;
 
+    // TODO Refactor to UI shared state (#11378)
     private List<String> locales;
 
-    private int pendingLocalesIndex;
-
-    private int timeoutInterval = -1;
-
+    // TODO Move to VaadinSession (#11409)
     private DragAndDropService dragAndDropService;
 
+    // TODO Refactor (#11412)
     private String requestThemeName;
 
-    private int maxInactiveInterval;
-
-    private ClientConnector highlightedConnector;
-
+    // TODO Refactor (#11413)
     private Map<String, Class<?>> publishedFileContexts = new HashMap<String, Class<?>>();
 
     /**
@@ -172,6 +113,7 @@ public abstract class AbstractCommunicationManager implements Serializable {
      */
     public AbstractCommunicationManager(VaadinSession session) {
         this.session = session;
+        // TODO Common to all sessions - handle at VaadinService level
         session.addRequestHandler(getBootstrapHandler());
         session.addRequestHandler(UNSUPPORTED_BROWSER_HANDLER);
         session.addRequestHandler(CONNECTOR_RESOURCE_HANDLER);
@@ -182,557 +124,6 @@ public abstract class AbstractCommunicationManager implements Serializable {
         return session;
     }
 
-    private static final int LF = "\n".getBytes()[0];
-
-    private static final String CRLF = "\r\n";
-
-    private static final String UTF8 = "UTF-8";
-
-    private static String readLine(InputStream stream) throws IOException {
-        ByteArrayOutputStream bout = new ByteArrayOutputStream();
-        int readByte = stream.read();
-        while (readByte != LF) {
-            bout.write(readByte);
-            readByte = stream.read();
-        }
-        byte[] bytes = bout.toByteArray();
-        return new String(bytes, 0, bytes.length - 1, UTF8);
-    }
-
-    /**
-     * Method used to stream content from a multipart request (either from
-     * servlet or portlet request) to given StreamVariable
-     * 
-     * 
-     * @param request
-     * @param response
-     * @param streamVariable
-     * @param owner
-     * @param boundary
-     * @throws IOException
-     */
-    protected void doHandleSimpleMultipartFileUpload(VaadinRequest request,
-            VaadinResponse response, StreamVariable streamVariable,
-            String variableName, ClientConnector owner, String boundary)
-            throws IOException {
-        // multipart parsing, supports only one file for request, but that is
-        // fine for our current terminal
-
-        final InputStream inputStream = request.getInputStream();
-
-        int contentLength = request.getContentLength();
-
-        boolean atStart = false;
-        boolean firstFileFieldFound = false;
-
-        String rawfilename = "unknown";
-        String rawMimeType = "application/octet-stream";
-
-        /*
-         * Read the stream until the actual file starts (empty line). Read
-         * filename and content type from multipart headers.
-         */
-        while (!atStart) {
-            String readLine = readLine(inputStream);
-            contentLength -= (readLine.getBytes(UTF8).length + CRLF.length());
-            if (readLine.startsWith("Content-Disposition:")
-                    && readLine.indexOf("filename=") > 0) {
-                rawfilename = readLine.replaceAll(".*filename=", "");
-                char quote = rawfilename.charAt(0);
-                rawfilename = rawfilename.substring(1);
-                rawfilename = rawfilename.substring(0,
-                        rawfilename.indexOf(quote));
-                firstFileFieldFound = true;
-            } else if (firstFileFieldFound && readLine.equals("")) {
-                atStart = true;
-            } else if (readLine.startsWith("Content-Type")) {
-                rawMimeType = readLine.split(": ")[1];
-            }
-        }
-
-        contentLength -= (boundary.length() + CRLF.length() + 2
-                * DASHDASH.length() + CRLF.length());
-
-        /*
-         * Reads bytes from the underlying stream. Compares the read bytes to
-         * the boundary string and returns -1 if met.
-         * 
-         * The matching happens so that if the read byte equals to the first
-         * char of boundary string, the stream goes to "buffering mode". In
-         * buffering mode bytes are read until the character does not match the
-         * corresponding from boundary string or the full boundary string is
-         * found.
-         * 
-         * Note, if this is someday needed elsewhere, don't shoot yourself to
-         * foot and split to a top level helper class.
-         */
-        InputStream simpleMultiPartReader = new SimpleMultiPartInputStream(
-                inputStream, boundary);
-
-        /*
-         * Should report only the filename even if the browser sends the path
-         */
-        final String filename = removePath(rawfilename);
-        final String mimeType = rawMimeType;
-
-        try {
-            // TODO Shouldn't this check connectorEnabled?
-            if (owner == null) {
-                throw new UploadException(
-                        "File upload ignored because the connector for the stream variable was not found");
-            }
-            if (owner instanceof Component) {
-                if (((Component) owner).isReadOnly()) {
-                    throw new UploadException(
-                            "Warning: file upload ignored because the componente was read-only");
-                }
-            }
-            boolean forgetVariable = streamToReceiver(simpleMultiPartReader,
-                    streamVariable, filename, mimeType, contentLength);
-            if (forgetVariable) {
-                cleanStreamVariable(owner, variableName);
-            }
-        } catch (Exception e) {
-            session.lock();
-            try {
-                handleConnectorRelatedException(owner, e);
-            } finally {
-                session.unlock();
-            }
-        }
-        sendUploadResponse(request, response);
-
-    }
-
-    /**
-     * Used to stream plain file post (aka XHR2.post(File))
-     * 
-     * @param request
-     * @param response
-     * @param streamVariable
-     * @param owner
-     * @param contentLength
-     * @throws IOException
-     */
-    protected void doHandleXhrFilePost(VaadinRequest request,
-            VaadinResponse response, StreamVariable streamVariable,
-            String variableName, ClientConnector owner, int contentLength)
-            throws IOException {
-
-        // These are unknown in filexhr ATM, maybe add to Accept header that
-        // is accessible in portlets
-        final String filename = "unknown";
-        final String mimeType = filename;
-        final InputStream stream = request.getInputStream();
-        try {
-            /*
-             * safe cast as in GWT terminal all variable owners are expected to
-             * be components.
-             */
-            Component component = (Component) owner;
-            if (component.isReadOnly()) {
-                throw new UploadException(
-                        "Warning: file upload ignored because the component was read-only");
-            }
-            boolean forgetVariable = streamToReceiver(stream, streamVariable,
-                    filename, mimeType, contentLength);
-            if (forgetVariable) {
-                cleanStreamVariable(owner, variableName);
-            }
-        } catch (Exception e) {
-            session.lock();
-            try {
-                handleConnectorRelatedException(owner, e);
-            } finally {
-                session.unlock();
-            }
-        }
-        sendUploadResponse(request, response);
-    }
-
-    /**
-     * @param in
-     * @param streamVariable
-     * @param filename
-     * @param type
-     * @param contentLength
-     * @return true if the streamvariable has informed that the terminal can
-     *         forget this variable
-     * @throws UploadException
-     */
-    protected final boolean streamToReceiver(final InputStream in,
-            StreamVariable streamVariable, String filename, String type,
-            int contentLength) throws UploadException {
-        if (streamVariable == null) {
-            throw new IllegalStateException(
-                    "StreamVariable for the post not found");
-        }
-
-        final VaadinSession session = getSession();
-
-        OutputStream out = null;
-        int totalBytes = 0;
-        StreamingStartEventImpl startedEvent = new StreamingStartEventImpl(
-                filename, type, contentLength);
-        try {
-            boolean listenProgress;
-            session.lock();
-            try {
-                streamVariable.streamingStarted(startedEvent);
-                out = streamVariable.getOutputStream();
-                listenProgress = streamVariable.listenProgress();
-            } finally {
-                session.unlock();
-            }
-
-            // Gets the output target stream
-            if (out == null) {
-                throw new NoOutputStreamException();
-            }
-
-            if (null == in) {
-                // No file, for instance non-existent filename in html upload
-                throw new NoInputStreamException();
-            }
-
-            final byte buffer[] = new byte[MAX_UPLOAD_BUFFER_SIZE];
-            int bytesReadToBuffer = 0;
-            while ((bytesReadToBuffer = in.read(buffer)) > 0) {
-                out.write(buffer, 0, bytesReadToBuffer);
-                totalBytes += bytesReadToBuffer;
-                if (listenProgress) {
-                    // update progress if listener set and contentLength
-                    // received
-                    session.lock();
-                    try {
-                        StreamingProgressEventImpl progressEvent = new StreamingProgressEventImpl(
-                                filename, type, contentLength, totalBytes);
-                        streamVariable.onProgress(progressEvent);
-                    } finally {
-                        session.unlock();
-                    }
-                }
-                if (streamVariable.isInterrupted()) {
-                    throw new UploadInterruptedException();
-                }
-            }
-
-            // upload successful
-            out.close();
-            StreamingEndEvent event = new StreamingEndEventImpl(filename, type,
-                    totalBytes);
-            session.lock();
-            try {
-                streamVariable.streamingFinished(event);
-            } finally {
-                session.unlock();
-            }
-
-        } catch (UploadInterruptedException e) {
-            // Download interrupted by application code
-            tryToCloseStream(out);
-            StreamingErrorEvent event = new StreamingErrorEventImpl(filename,
-                    type, contentLength, totalBytes, e);
-            session.lock();
-            try {
-                streamVariable.streamingFailed(event);
-            } finally {
-                session.unlock();
-            }
-            // Note, we are not throwing interrupted exception forward as it is
-            // not a terminal level error like all other exception.
-        } catch (final Exception e) {
-            tryToCloseStream(out);
-            session.lock();
-            try {
-                StreamingErrorEvent event = new StreamingErrorEventImpl(
-                        filename, type, contentLength, totalBytes, e);
-                streamVariable.streamingFailed(event);
-                // throw exception for terminal to be handled (to be passed to
-                // terminalErrorHandler)
-                throw new UploadException(e);
-            } finally {
-                session.unlock();
-            }
-        }
-        return startedEvent.isDisposed();
-    }
-
-    static void tryToCloseStream(OutputStream out) {
-        try {
-            // try to close output stream (e.g. file handle)
-            if (out != null) {
-                out.close();
-            }
-        } catch (IOException e1) {
-            // NOP
-        }
-    }
-
-    /**
-     * Removes any possible path information from the filename and returns the
-     * filename. Separators / and \\ are used.
-     * 
-     * @param name
-     * @return
-     */
-    private static String removePath(String filename) {
-        if (filename != null) {
-            filename = filename.replaceAll("^.*[/\\\\]", "");
-        }
-
-        return filename;
-    }
-
-    /**
-     * TODO document
-     * 
-     * @param request
-     * @param response
-     * @throws IOException
-     */
-    protected void sendUploadResponse(VaadinRequest request,
-            VaadinResponse response) throws IOException {
-        response.setContentType("text/html");
-        final OutputStream out = response.getOutputStream();
-        final PrintWriter outWriter = new PrintWriter(new BufferedWriter(
-                new OutputStreamWriter(out, "UTF-8")));
-        outWriter.print("<html><body>download handled</body></html>");
-        outWriter.flush();
-        out.close();
-    }
-
-    /**
-     * Internally process a UIDL request from the client.
-     * 
-     * This method calls
-     * {@link #handleVariables(VaadinRequest, VaadinResponse, Callback, VaadinSession, UI)}
-     * to process any changes to variables by the client and then repaints
-     * affected components using {@link #paintAfterVariableChanges()}.
-     * 
-     * Also, some cleanup is done when a request arrives for an session that has
-     * already been closed.
-     * 
-     * The method handleUidlRequest(...) in subclasses should call this method.
-     * 
-     * TODO better documentation
-     * 
-     * @param request
-     * @param response
-     * @param callback
-     * @param uI
-     *            target window for the UIDL request, can be null if target not
-     *            found
-     * @throws IOException
-     * @throws InvalidUIDLSecurityKeyException
-     * @throws JSONException
-     */
-    public void handleUidlRequest(VaadinRequest request,
-            VaadinResponse response, Callback callback, UI uI)
-            throws IOException, InvalidUIDLSecurityKeyException, JSONException {
-
-        checkWidgetsetVersion(request);
-        requestThemeName = request.getParameter("theme");
-        maxInactiveInterval = request.getWrappedSession()
-                .getMaxInactiveInterval();
-        // repaint requested or session has timed out and new one is created
-        boolean repaintAll;
-        final OutputStream out;
-
-        repaintAll = (request
-                .getParameter(ApplicationConstants.URL_PARAMETER_REPAINT_ALL) != null);
-        // || (request.getSession().isNew()); FIXME What the h*ll is this??
-        out = response.getOutputStream();
-
-        boolean analyzeLayouts = false;
-        if (repaintAll) {
-            // analyzing can be done only with repaintAll
-            analyzeLayouts = (request
-                    .getParameter(ApplicationConstants.PARAM_ANALYZE_LAYOUTS) != null);
-
-            String pid = request
-                    .getParameter(ApplicationConstants.PARAM_HIGHLIGHT_CONNECTOR);
-            if (pid != null) {
-                highlightedConnector = uI.getConnectorTracker().getConnector(
-                        pid);
-                highlightConnector(highlightedConnector);
-            }
-        }
-
-        final PrintWriter outWriter = new PrintWriter(new BufferedWriter(
-                new OutputStreamWriter(out, "UTF-8")));
-
-        // The rest of the process is synchronized with the session
-        // in order to guarantee that no parallel variable handling is
-        // made
-        session.lock();
-        try {
-
-            // Verify that there's an UI
-            if (uI == null) {
-                // This should not happen, no windows exists but
-                // session is still open.
-                getLogger().warning("Could not get UI for session");
-                return;
-            }
-
-            session.setLastRequestTimestamp(System.currentTimeMillis());
-
-            // Change all variables based on request parameters
-            if (!handleVariables(request, response, callback, session, uI)) {
-
-                // var inconsistency; the client is probably out-of-sync
-                SystemMessages ci = response.getService().getSystemMessages(
-                        uI.getLocale(), request);
-                String msg = ci.getOutOfSyncMessage();
-                String cap = ci.getOutOfSyncCaption();
-                if (msg != null || cap != null) {
-                    callback.criticalNotification(request, response, cap, msg,
-                            null, ci.getOutOfSyncURL());
-                    // will reload page after this
-                    return;
-                }
-                // No message to show, let's just repaint all.
-                repaintAll = true;
-            }
-
-            paintAfterVariableChanges(request, response, callback, repaintAll,
-                    outWriter, uI, analyzeLayouts);
-            postPaint(uI);
-        } finally {
-            session.unlock();
-        }
-
-        outWriter.close();
-        requestThemeName = null;
-    }
-
-    /**
-     * Checks that the version reported by the client (widgetset) matches that
-     * of the server.
-     * 
-     * @param request
-     */
-    private void checkWidgetsetVersion(VaadinRequest request) {
-        String widgetsetVersion = request.getParameter("v-wsver");
-        if (widgetsetVersion == null) {
-            // Only check when the widgetset version is reported. It is reported
-            // in the first UIDL request (not the initial request as it is a
-            // plain GET /)
-            return;
-        }
-
-        if (!Version.getFullVersion().equals(widgetsetVersion)) {
-            getLogger().warning(
-                    String.format(Constants.WIDGETSET_MISMATCH_INFO,
-                            Version.getFullVersion(), widgetsetVersion));
-        }
-    }
-
-    /**
-     * Method called after the paint phase while still being synchronized on the
-     * session
-     * 
-     * @param uI
-     * 
-     */
-    protected void postPaint(UI uI) {
-        // Remove connectors that have been detached from the session during
-        // handling of the request
-        uI.getConnectorTracker().cleanConnectorMap();
-    }
-
-    protected void highlightConnector(ClientConnector highlightedConnector) {
-        StringBuilder sb = new StringBuilder();
-        sb.append("*** Debug details of a connector:  *** \n");
-        sb.append("Type: ");
-        sb.append(highlightedConnector.getClass().getName());
-        sb.append("\nId:");
-        sb.append(highlightedConnector.getConnectorId());
-        if (highlightedConnector instanceof Component) {
-            Component component = (Component) highlightedConnector;
-            if (component.getCaption() != null) {
-                sb.append("\nCaption:");
-                sb.append(component.getCaption());
-            }
-        }
-        printHighlightedConnectorHierarchy(sb, highlightedConnector);
-        getLogger().info(sb.toString());
-    }
-
-    protected void printHighlightedConnectorHierarchy(StringBuilder sb,
-            ClientConnector connector) {
-        LinkedList<ClientConnector> h = new LinkedList<ClientConnector>();
-        h.add(connector);
-        ClientConnector parent = connector.getParent();
-        while (parent != null) {
-            h.addFirst(parent);
-            parent = parent.getParent();
-        }
-
-        sb.append("\nConnector hierarchy:\n");
-        VaadinSession session2 = connector.getUI().getSession();
-        sb.append(session2.getClass().getName());
-        sb.append("(");
-        sb.append(session2.getClass().getSimpleName());
-        sb.append(".java");
-        sb.append(":1)");
-        int l = 1;
-        for (ClientConnector connector2 : h) {
-            sb.append("\n");
-            for (int i = 0; i < l; i++) {
-                sb.append("  ");
-            }
-            l++;
-            Class<? extends ClientConnector> connectorClass = connector2
-                    .getClass();
-            Class<?> topClass = connectorClass;
-            while (topClass.getEnclosingClass() != null) {
-                topClass = topClass.getEnclosingClass();
-            }
-            sb.append(connectorClass.getName());
-            sb.append("(");
-            sb.append(topClass.getSimpleName());
-            sb.append(".java:1)");
-        }
-    }
-
-    /**
-     * TODO document
-     * 
-     * @param request
-     * @param response
-     * @param callback
-     * @param repaintAll
-     * @param outWriter
-     * @param window
-     * @param analyzeLayouts
-     * @throws PaintException
-     * @throws IOException
-     * @throws JSONException
-     */
-    private void paintAfterVariableChanges(VaadinRequest request,
-            VaadinResponse response, Callback callback, boolean repaintAll,
-            final PrintWriter outWriter, UI uI, boolean analyzeLayouts)
-            throws PaintException, IOException, JSONException {
-        openJsonMessage(outWriter, response);
-
-        // security key
-        Object writeSecurityTokenFlag = request
-                .getAttribute(WRITE_SECURITY_TOKEN_FLAG);
-
-        if (writeSecurityTokenFlag != null) {
-            outWriter.print(getSecurityKeyUIDL(request));
-        }
-
-        writeUidlResponse(request, repaintAll, outWriter, uI, analyzeLayouts);
-
-        closeJsonMessage(outWriter);
-
-        outWriter.close();
-
-    }
-
     /**
      * Gets the security key (and generates one if needed) as UIDL.
      * 
@@ -769,443 +160,10 @@ public abstract class AbstractCommunicationManager implements Serializable {
         return seckey;
     }
 
-    @SuppressWarnings("unchecked")
-    public void writeUidlResponse(VaadinRequest request, boolean repaintAll,
-            final PrintWriter outWriter, UI ui, boolean analyzeLayouts)
-            throws PaintException, JSONException {
-        ArrayList<ClientConnector> dirtyVisibleConnectors = new ArrayList<ClientConnector>();
-        VaadinSession session = ui.getSession();
-        // Paints components
-        ConnectorTracker uiConnectorTracker = ui.getConnectorTracker();
-        getLogger().log(Level.FINE, "* Creating response to client");
-        if (repaintAll) {
-            getClientCache(ui).clear();
-            uiConnectorTracker.markAllConnectorsDirty();
-            uiConnectorTracker.markAllClientSidesUninitialized();
-
-            // Reset sent locales
-            locales = null;
-            requireLocale(session.getLocale().toString());
-        }
-
-        dirtyVisibleConnectors
-                .addAll(getDirtyVisibleConnectors(uiConnectorTracker));
-
-        getLogger().log(Level.FINE, "Found {0} dirty connectors to paint",
-                dirtyVisibleConnectors.size());
-        for (ClientConnector connector : dirtyVisibleConnectors) {
-            boolean initialized = uiConnectorTracker
-                    .isClientSideInitialized(connector);
-            connector.beforeClientResponse(!initialized);
-        }
-
-        uiConnectorTracker.setWritingResponse(true);
-        try {
-            outWriter.print("\"changes\":[");
-
-            List<InvalidLayout> invalidComponentRelativeSizes = null;
-
-            JsonPaintTarget paintTarget = new JsonPaintTarget(this, outWriter,
-                    !repaintAll);
-            legacyPaint(paintTarget, dirtyVisibleConnectors);
-
-            if (analyzeLayouts) {
-                invalidComponentRelativeSizes = ComponentSizeValidator
-                        .validateComponentRelativeSizes(ui.getContent(), null,
-                                null);
-
-                // Also check any existing subwindows
-                if (ui.getWindows() != null) {
-                    for (Window subWindow : ui.getWindows()) {
-                        invalidComponentRelativeSizes = ComponentSizeValidator
-                                .validateComponentRelativeSizes(
-                                        subWindow.getContent(),
-                                        invalidComponentRelativeSizes, null);
-                    }
-                }
-            }
-
-            paintTarget.close();
-            outWriter.print("], "); // close changes
-
-            // send shared state to client
-
-            // for now, send the complete state of all modified and new
-            // components
-
-            // Ideally, all this would be sent before "changes", but that causes
-            // complications with legacy components that create sub-components
-            // in their paint phase. Nevertheless, this will be processed on the
-            // client after component creation but before legacy UIDL
-            // processing.
-            JSONObject sharedStates = new JSONObject();
-            for (ClientConnector connector : dirtyVisibleConnectors) {
-                // encode and send shared state
-                try {
-                    JSONObject stateJson = connector.encodeState();
-
-                    if (stateJson != null && stateJson.length() != 0) {
-                        sharedStates.put(connector.getConnectorId(), stateJson);
-                    }
-                } catch (JSONException e) {
-                    throw new PaintException(
-                            "Failed to serialize shared state for connector "
-                                    + connector.getClass().getName() + " ("
-                                    + connector.getConnectorId() + "): "
-                                    + e.getMessage(), e);
-                }
-            }
-            outWriter.print("\"state\":");
-            outWriter.append(sharedStates.toString());
-            outWriter.print(", "); // close states
-
-            // TODO This should be optimized. The type only needs to be
-            // sent once for each connector id + on refresh. Use the same cache
-            // as
-            // widget mapping
-
-            JSONObject connectorTypes = new JSONObject();
-            for (ClientConnector connector : dirtyVisibleConnectors) {
-                String connectorType = paintTarget.getTag(connector);
-                try {
-                    connectorTypes.put(connector.getConnectorId(),
-                            connectorType);
-                } catch (JSONException e) {
-                    throw new PaintException(
-                            "Failed to send connector type for connector "
-                                    + connector.getConnectorId() + ": "
-                                    + e.getMessage(), e);
-                }
-            }
-            outWriter.print("\"types\":");
-            outWriter.append(connectorTypes.toString());
-            outWriter.print(", "); // close states
-
-            // Send update hierarchy information to the client.
-
-            // This could be optimized aswell to send only info if hierarchy has
-            // actually changed. Much like with the shared state. Note though
-            // that an empty hierarchy is information aswell (e.g. change from 1
-            // child to 0 children)
-
-            outWriter.print("\"hierarchy\":");
-
-            JSONObject hierarchyInfo = new JSONObject();
-            for (ClientConnector connector : dirtyVisibleConnectors) {
-                String connectorId = connector.getConnectorId();
-                JSONArray children = new JSONArray();
-
-                for (ClientConnector child : AbstractClientConnector
-                        .getAllChildrenIterable(connector)) {
-                    if (isConnectorVisibleToClient(child)) {
-                        children.put(child.getConnectorId());
-                    }
-                }
-                try {
-                    hierarchyInfo.put(connectorId, children);
-                } catch (JSONException e) {
-                    throw new PaintException(
-                            "Failed to send hierarchy information about "
-                                    + connectorId + " to the client: "
-                                    + e.getMessage(), e);
-                }
-            }
-            outWriter.append(hierarchyInfo.toString());
-            outWriter.print(", "); // close hierarchy
-
-            uiConnectorTracker.markAllConnectorsClean();
-
-            // send server to client RPC calls for components in the UI, in call
-            // order
-
-            // collect RPC calls from components in the UI in the order in
-            // which they were performed, remove the calls from components
-
-            LinkedList<ClientConnector> rpcPendingQueue = new LinkedList<ClientConnector>(
-                    dirtyVisibleConnectors);
-            List<ClientMethodInvocation> pendingInvocations = collectPendingRpcCalls(dirtyVisibleConnectors);
-
-            JSONArray rpcCalls = new JSONArray();
-            for (ClientMethodInvocation invocation : pendingInvocations) {
-                // add invocation to rpcCalls
-                try {
-                    JSONArray invocationJson = new JSONArray();
-                    invocationJson.put(invocation.getConnector()
-                            .getConnectorId());
-                    invocationJson.put(invocation.getInterfaceName());
-                    invocationJson.put(invocation.getMethodName());
-                    JSONArray paramJson = new JSONArray();
-                    for (int i = 0; i < invocation.getParameterTypes().length; ++i) {
-                        Type parameterType = invocation.getParameterTypes()[i];
-                        Object referenceParameter = null;
-                        // TODO Use default values for RPC parameter types
-                        // if (!JsonCodec.isInternalType(parameterType)) {
-                        // try {
-                        // referenceParameter = parameterType.newInstance();
-                        // } catch (Exception e) {
-                        // logger.log(Level.WARNING,
-                        // "Error creating reference object for parameter of type "
-                        // + parameterType.getName());
-                        // }
-                        // }
-                        EncodeResult encodeResult = JsonCodec.encode(
-                                invocation.getParameters()[i],
-                                referenceParameter, parameterType,
-                                ui.getConnectorTracker());
-                        paramJson.put(encodeResult.getEncodedValue());
-                    }
-                    invocationJson.put(paramJson);
-                    rpcCalls.put(invocationJson);
-                } catch (JSONException e) {
-                    throw new PaintException(
-                            "Failed to serialize RPC method call parameters for connector "
-                                    + invocation.getConnector()
-                                            .getConnectorId() + " method "
-                                    + invocation.getInterfaceName() + "."
-                                    + invocation.getMethodName() + ": "
-                                    + e.getMessage(), e);
-                }
-
-            }
-
-            if (rpcCalls.length() > 0) {
-                outWriter.print("\"rpc\" : ");
-                outWriter.append(rpcCalls.toString());
-                outWriter.print(", "); // close rpc
-            }
-
-            outWriter.print("\"meta\" : {");
-            boolean metaOpen = false;
-
-            if (repaintAll) {
-                metaOpen = true;
-                outWriter.write("\"repaintAll\":true");
-                if (analyzeLayouts) {
-                    outWriter.write(", \"invalidLayouts\":");
-                    outWriter.write("[");
-                    if (invalidComponentRelativeSizes != null) {
-                        boolean first = true;
-                        for (InvalidLayout invalidLayout : invalidComponentRelativeSizes) {
-                            if (!first) {
-                                outWriter.write(",");
-                            } else {
-                                first = false;
-                            }
-                            invalidLayout.reportErrors(outWriter, this,
-                                    System.err);
-                        }
-                    }
-                    outWriter.write("]");
-                }
-                if (highlightedConnector != null) {
-                    outWriter.write(", \"hl\":\"");
-                    outWriter.write(highlightedConnector.getConnectorId());
-                    outWriter.write("\"");
-                    highlightedConnector = null;
-                }
-            }
-
-            SystemMessages ci = request.getService().getSystemMessages(
-                    ui.getLocale(), request);
-
-            // meta instruction for client to enable auto-forward to
-            // sessionExpiredURL after timer expires.
-            if (ci != null && ci.getSessionExpiredMessage() == null
-                    && ci.getSessionExpiredCaption() == null
-                    && ci.isSessionExpiredNotificationEnabled()) {
-                int newTimeoutInterval = getTimeoutInterval();
-                if (repaintAll || (timeoutInterval != newTimeoutInterval)) {
-                    String escapedURL = ci.getSessionExpiredURL() == null ? ""
-                            : ci.getSessionExpiredURL().replace("/", "\\/");
-                    if (metaOpen) {
-                        outWriter.write(",");
-                    }
-                    outWriter.write("\"timedRedirect\":{\"interval\":"
-                            + (newTimeoutInterval + 15) + ",\"url\":\""
-                            + escapedURL + "\"}");
-                    metaOpen = true;
-                }
-                timeoutInterval = newTimeoutInterval;
-            }
-
-            outWriter.print("}, \"resources\" : {");
-
-            // Precache custom layouts
-
-            // TODO We should only precache the layouts that are not
-            // cached already (plagiate from usedPaintableTypes)
-            int resourceIndex = 0;
-            for (final Iterator<Object> i = paintTarget.getUsedResources()
-                    .iterator(); i.hasNext();) {
-                final String resource = (String) i.next();
-                InputStream is = null;
-                try {
-                    is = getThemeResourceAsStream(ui, getTheme(ui), resource);
-                } catch (final Exception e) {
-                    // FIXME: Handle exception
-                    getLogger().log(Level.FINER,
-                            "Failed to get theme resource stream.", e);
-                }
-                if (is != null) {
-
-                    outWriter.print((resourceIndex++ > 0 ? ", " : "") + "\""
-                            + resource + "\" : ");
-                    final StringBuffer layout = new StringBuffer();
-
-                    try {
-                        final InputStreamReader r = new InputStreamReader(is,
-                                "UTF-8");
-                        final char[] buffer = new char[20000];
-                        int charsRead = 0;
-                        while ((charsRead = r.read(buffer)) > 0) {
-                            layout.append(buffer, 0, charsRead);
-                        }
-                        r.close();
-                    } catch (final java.io.IOException e) {
-                        // FIXME: Handle exception
-                        getLogger().log(Level.INFO, "Resource transfer failed",
-                                e);
-                    }
-                    outWriter.print("\""
-                            + JsonPaintTarget.escapeJSON(layout.toString())
-                            + "\"");
-                } else {
-                    // FIXME: Handle exception
-                    getLogger().severe("CustomLayout not found: " + resource);
-                }
-            }
-            outWriter.print("}");
-
-            Collection<Class<? extends ClientConnector>> usedClientConnectors = paintTarget
-                    .getUsedClientConnectors();
-            boolean typeMappingsOpen = false;
-            ClientCache clientCache = getClientCache(ui);
-
-            List<Class<? extends ClientConnector>> newConnectorTypes = new ArrayList<Class<? extends ClientConnector>>();
-
-            for (Class<? extends ClientConnector> class1 : usedClientConnectors) {
-                if (clientCache.cache(class1)) {
-                    // client does not know the mapping key for this type, send
-                    // mapping to client
-                    newConnectorTypes.add(class1);
-
-                    if (!typeMappingsOpen) {
-                        typeMappingsOpen = true;
-                        outWriter.print(", \"typeMappings\" : { ");
-                    } else {
-                        outWriter.print(" , ");
-                    }
-                    String canonicalName = class1.getCanonicalName();
-                    outWriter.print("\"");
-                    outWriter.print(canonicalName);
-                    outWriter.print("\" : ");
-                    outWriter.print(getTagForType(class1));
-                }
-            }
-            if (typeMappingsOpen) {
-                outWriter.print(" }");
-            }
-
-            boolean typeInheritanceMapOpen = false;
-            if (typeMappingsOpen) {
-                // send the whole type inheritance map if any new mappings
-                for (Class<? extends ClientConnector> class1 : usedClientConnectors) {
-                    if (!ClientConnector.class.isAssignableFrom(class1
-                            .getSuperclass())) {
-                        continue;
-                    }
-                    if (!typeInheritanceMapOpen) {
-                        typeInheritanceMapOpen = true;
-                        outWriter.print(", \"typeInheritanceMap\" : { ");
-                    } else {
-                        outWriter.print(" , ");
-                    }
-                    outWriter.print("\"");
-                    outWriter.print(getTagForType(class1));
-                    outWriter.print("\" : ");
-                    outWriter
-                            .print(getTagForType((Class<? extends ClientConnector>) class1
-                                    .getSuperclass()));
-                }
-                if (typeInheritanceMapOpen) {
-                    outWriter.print(" }");
-                }
-            }
-
-            /*
-             * Ensure super classes come before sub classes to get script
-             * dependency order right. Sub class @JavaScript might assume that
-             * 
-             * @JavaScript defined by super class is already loaded.
-             */
-            Collections.sort(newConnectorTypes, new Comparator<Class<?>>() {
-                @Override
-                public int compare(Class<?> o1, Class<?> o2) {
-                    // TODO optimize using Class.isAssignableFrom?
-                    return hierarchyDepth(o1) - hierarchyDepth(o2);
-                }
-
-                private int hierarchyDepth(Class<?> type) {
-                    if (type == Object.class) {
-                        return 0;
-                    } else {
-                        return hierarchyDepth(type.getSuperclass()) + 1;
-                    }
-                }
-            });
-
-            List<String> scriptDependencies = new ArrayList<String>();
-            List<String> styleDependencies = new ArrayList<String>();
-
-            for (Class<? extends ClientConnector> class1 : newConnectorTypes) {
-                JavaScript jsAnnotation = class1
-                        .getAnnotation(JavaScript.class);
-                if (jsAnnotation != null) {
-                    for (String uri : jsAnnotation.value()) {
-                        scriptDependencies.add(registerDependency(uri, class1));
-                    }
-                }
-
-                StyleSheet styleAnnotation = class1
-                        .getAnnotation(StyleSheet.class);
-                if (styleAnnotation != null) {
-                    for (String uri : styleAnnotation.value()) {
-                        styleDependencies.add(registerDependency(uri, class1));
-                    }
-                }
-            }
-
-            // Include script dependencies in output if there are any
-            if (!scriptDependencies.isEmpty()) {
-                outWriter.print(", \"scriptDependencies\": "
-                        + new JSONArray(scriptDependencies).toString());
-            }
-
-            // Include style dependencies in output if there are any
-            if (!styleDependencies.isEmpty()) {
-                outWriter.print(", \"styleDependencies\": "
-                        + new JSONArray(styleDependencies).toString());
-            }
-
-            // add any pending locale definitions requested by the client
-            printLocaleDeclarations(outWriter);
-
-            if (dragAndDropService != null) {
-                dragAndDropService.printJSONResponse(outWriter);
-            }
-
-            for (ClientConnector connector : dirtyVisibleConnectors) {
-                uiConnectorTracker.markClientSideInitialized(connector);
-            }
-
-            assert (uiConnectorTracker.getDirtyConnectors().isEmpty()) : "Connectors have been marked as dirty during the end of the paint phase. This is most certainly not intended.";
-
-            writePerformanceData(outWriter);
-        } finally {
-            uiConnectorTracker.setWritingResponse(false);
-        }
-    }
-
+    /**
+     * @deprecated As of 7.1. See #11411.
+     */
+    @Deprecated
     public static JSONObject encodeState(ClientConnector connector,
             SharedState state) throws JSONException {
         UI uI = connector.getUI();
@@ -1243,8 +201,11 @@ public abstract class AbstractCommunicationManager implements Serializable {
      * Resolves a dependency URI, registering the URI with this
      * {@code AbstractCommunicationManager} if needed and returns a fully
      * qualified URI.
+     * 
+     * @deprecated As of 7.1. See #11413.
      */
-    private String registerDependency(String resourceUri, Class<?> context) {
+    @Deprecated
+    public String registerDependency(String resourceUri, Class<?> context) {
         try {
             URI uri = new URI(resourceUri);
             String protocol = uri.getScheme();
@@ -1268,6 +229,14 @@ public abstract class AbstractCommunicationManager implements Serializable {
         }
     }
 
+    /**
+     * @deprecated As of 7.1. See #11413.
+     */
+    @Deprecated
+    public Map<String, Class<?>> getDependencies() {
+        return publishedFileContexts;
+    }
+
     private String registerPublishedFile(String name, Class<?> context) {
         synchronized (publishedFileContexts) {
             // Add to map of names accepted by servePublishedFile
@@ -1288,75 +257,10 @@ public abstract class AbstractCommunicationManager implements Serializable {
     }
 
     /**
-     * Adds the performance timing data (used by TestBench 3) to the UIDL
-     * response.
+     * @deprecated As of 7.1. See #11410.
      */
-    private void writePerformanceData(final PrintWriter outWriter) {
-        outWriter.write(String.format(", \"timings\":[%d, %d]",
-                session.getCumulativeRequestDuration(),
-                session.getLastRequestDuration()));
-    }
-
-    private void legacyPaint(PaintTarget paintTarget,
-            ArrayList<ClientConnector> dirtyVisibleConnectors)
-            throws PaintException {
-        List<LegacyComponent> legacyComponents = new ArrayList<LegacyComponent>();
-        for (Connector connector : dirtyVisibleConnectors) {
-            // All Components that want to use paintContent must implement
-            // LegacyComponent
-            if (connector instanceof LegacyComponent) {
-                legacyComponents.add((LegacyComponent) connector);
-            }
-        }
-        sortByHierarchy((List) legacyComponents);
-        for (LegacyComponent c : legacyComponents) {
-            if (getLogger().isLoggable(Level.FINE)) {
-                getLogger().log(
-                        Level.FINE,
-                        "Painting LegacyComponent {0}@{1}",
-                        new Object[] { c.getClass().getName(),
-                                Integer.toHexString(c.hashCode()) });
-            }
-            paintTarget.startTag("change");
-            final String pid = c.getConnectorId();
-            paintTarget.addAttribute("pid", pid);
-            LegacyPaint.paint(c, paintTarget);
-            paintTarget.endTag("change");
-        }
-
-    }
-
-    private void sortByHierarchy(List<Component> paintables) {
-        // Vaadin 6 requires parents to be painted before children as component
-        // containers rely on that their updateFromUIDL method has been called
-        // before children start calling e.g. updateCaption
-        Collections.sort(paintables, new Comparator<Component>() {
-
-            @Override
-            public int compare(Component c1, Component c2) {
-                int depth1 = 0;
-                while (c1.getParent() != null) {
-                    depth1++;
-                    c1 = c1.getParent();
-                }
-                int depth2 = 0;
-                while (c2.getParent() != null) {
-                    depth2++;
-                    c2 = c2.getParent();
-                }
-                if (depth1 < depth2) {
-                    return -1;
-                }
-                if (depth1 > depth2) {
-                    return 1;
-                }
-                return 0;
-            }
-        });
-
-    }
-
-    private ClientCache getClientCache(UI uI) {
+    @Deprecated
+    public ClientCache getClientCache(UI uI) {
         Integer uiId = Integer.valueOf(uI.getUIId());
         ClientCache cache = uiToClientCache.get(uiId);
         if (cache == null) {
@@ -1372,11 +276,14 @@ public abstract class AbstractCommunicationManager implements Serializable {
      * of connectors, the contextual visibility of its first Component ancestor
      * is used. If no Component ancestor is found, the connector is not visible.
      * 
+     * @deprecated As of 7.1. See #11411.
+     * 
      * @param connector
      *            The connector to check
      * @return <code>true</code> if the connector is visible to the client,
      *         <code>false</code> otherwise
      */
+    @Deprecated
     public static boolean isConnectorVisibleToClient(ClientConnector connector) {
         if (connector instanceof Component) {
             return isComponentVisibleToClient((Component) connector);
@@ -1394,10 +301,13 @@ public abstract class AbstractCommunicationManager implements Serializable {
      * Checks if the component should be visible to the client. Returns false if
      * the child should not be sent to the client, true otherwise.
      * 
+     * @deprecated As of 7.1. See #11411.
+     * 
      * @param child
      *            The child to check
      * @return true if the child is visible to the client, false otherwise
      */
+    @Deprecated
     public static boolean isComponentVisibleToClient(Component child) {
         if (!child.isVisible()) {
             return false;
@@ -1423,71 +333,18 @@ public abstract class AbstractCommunicationManager implements Serializable {
         }
     }
 
-    private static class NullIterator<E> implements Iterator<E> {
-
-        @Override
-        public boolean hasNext() {
-            return false;
-        }
-
-        @Override
-        public E next() {
-            return null;
-        }
-
-        @Override
-        public void remove() {
-        }
-
-    }
-
     /**
-     * Collects all pending RPC calls from listed {@link ClientConnector}s and
-     * clears their RPC queues.
-     * 
-     * @param rpcPendingQueue
-     *            list of {@link ClientConnector} of interest
-     * @return ordered list of pending RPC calls
+     * @deprecated As of 7.1. Likely to be removed or replaced in the future.
      */
-    private List<ClientMethodInvocation> collectPendingRpcCalls(
-            List<ClientConnector> rpcPendingQueue) {
-        List<ClientMethodInvocation> pendingInvocations = new ArrayList<ClientMethodInvocation>();
-        for (ClientConnector connector : rpcPendingQueue) {
-            List<ClientMethodInvocation> paintablePendingRpc = connector
-                    .retrievePendingRpcCalls();
-            if (null != paintablePendingRpc && !paintablePendingRpc.isEmpty()) {
-                List<ClientMethodInvocation> oldPendingRpc = pendingInvocations;
-                int totalCalls = pendingInvocations.size()
-                        + paintablePendingRpc.size();
-                pendingInvocations = new ArrayList<ClientMethodInvocation>(
-                        totalCalls);
-
-                // merge two ordered comparable lists
-                for (int destIndex = 0, oldIndex = 0, paintableIndex = 0; destIndex < totalCalls; destIndex++) {
-                    if (paintableIndex >= paintablePendingRpc.size()
-                            || (oldIndex < oldPendingRpc.size() && ((Comparable<ClientMethodInvocation>) oldPendingRpc
-                                    .get(oldIndex))
-                                    .compareTo(paintablePendingRpc
-                                            .get(paintableIndex)) <= 0)) {
-                        pendingInvocations.add(oldPendingRpc.get(oldIndex++));
-                    } else {
-                        pendingInvocations.add(paintablePendingRpc
-                                .get(paintableIndex++));
-                    }
-                }
-            }
-        }
-        return pendingInvocations;
-    }
-
-    protected abstract InputStream getThemeResourceAsStream(UI uI,
+    @Deprecated
+    public abstract InputStream getThemeResourceAsStream(UI uI,
             String themeName, String resource);
 
-    private int getTimeoutInterval() {
-        return maxInactiveInterval;
-    }
-
-    private String getTheme(UI uI) {
+    /**
+     * @deprecated As of 7.1. See #11412.
+     */
+    @Deprecated
+    public String getTheme(UI uI) {
         String themeName = uI.getTheme();
         String requestThemeName = getRequestTheme();
 
@@ -1505,391 +362,10 @@ public abstract class AbstractCommunicationManager implements Serializable {
     }
 
     /**
-     * Returns false if the cross site request forgery protection is turned off.
-     * 
-     * @param session
-     * @return false if the XSRF is turned off, true otherwise
-     */
-    public boolean isXSRFEnabled(VaadinSession session) {
-        return session.getConfiguration().isXsrfProtectionEnabled();
-    }
-
-    /**
-     * TODO document
-     * 
-     * If this method returns false, something was submitted that we did not
-     * expect; this is probably due to the client being out-of-sync and sending
-     * variable changes for non-existing pids
-     * 
-     * @return true if successful, false if there was an inconsistency
-     */
-    private boolean handleVariables(VaadinRequest request,
-            VaadinResponse response, Callback callback, VaadinSession session,
-            UI uI) throws IOException, InvalidUIDLSecurityKeyException,
-            JSONException {
-        boolean success = true;
-
-        String changes = getRequestPayload(request);
-        if (changes != null) {
-
-            // Manage bursts one by one
-            final String[] bursts = changes.split(String
-                    .valueOf(VAR_BURST_SEPARATOR));
-
-            // Security: double cookie submission pattern unless disabled by
-            // property
-            if (isXSRFEnabled(session)) {
-                if (bursts.length == 1 && "init".equals(bursts[0])) {
-                    // init request; don't handle any variables, key sent in
-                    // response.
-                    request.setAttribute(WRITE_SECURITY_TOKEN_FLAG, true);
-                    return true;
-                } else {
-                    // ApplicationServlet has stored the security token in the
-                    // session; check that it matched the one sent in the UIDL
-                    String sessId = (String) request
-                            .getWrappedSession()
-                            .getAttribute(
-                                    ApplicationConstants.UIDL_SECURITY_TOKEN_ID);
-
-                    if (sessId == null || !sessId.equals(bursts[0])) {
-                        throw new InvalidUIDLSecurityKeyException(
-                                "Security key mismatch");
-                    }
-                }
-
-            }
-
-            for (int bi = 1; bi < bursts.length; bi++) {
-                // unescape any encoded separator characters in the burst
-                final String burst = unescapeBurst(bursts[bi]);
-                success &= handleBurst(request, uI, burst);
-
-                // In case that there were multiple bursts, we know that this is
-                // a special synchronous case for closing window. Thus we are
-                // not interested in sending any UIDL changes back to client.
-                // Still we must clear component tree between bursts to ensure
-                // that no removed components are updated. The painting after
-                // the last burst is handled normally by the calling method.
-                if (bi < bursts.length - 1) {
-
-                    // We will be discarding all changes
-                    final PrintWriter outWriter = new PrintWriter(
-                            new CharArrayWriter());
-
-                    paintAfterVariableChanges(request, response, callback,
-                            true, outWriter, uI, false);
-
-                }
-
-            }
-        }
-        /*
-         * Note that we ignore inconsistencies while handling unload request.
-         * The client can't remove invalid variable changes from the burst, and
-         * we don't have the required logic implemented on the server side. E.g.
-         * a component is removed in a previous burst.
-         */
-        return success;
-    }
-
-    /**
-     * Processes a message burst received from the client.
-     * 
-     * A burst can contain any number of RPC calls, including legacy variable
-     * change calls that are processed separately.
-     * 
-     * Consecutive changes to the value of the same variable are combined and
-     * changeVariables() is only called once for them. This preserves the Vaadin
-     * 6 semantics for components and add-ons that do not use Vaadin 7 RPC
-     * directly.
-     * 
-     * @param source
-     * @param uI
-     *            the UI receiving the burst
-     * @param burst
-     *            the content of the burst as a String to be parsed
-     * @return true if the processing of the burst was successful and there were
-     *         no messages to non-existent components
-     */
-    public boolean handleBurst(VaadinRequest source, UI uI, final String burst) {
-        boolean success = true;
-        try {
-            Set<Connector> enabledConnectors = new HashSet<Connector>();
-
-            List<MethodInvocation> invocations = parseInvocations(
-                    uI.getConnectorTracker(), burst);
-            for (MethodInvocation invocation : invocations) {
-                final ClientConnector connector = getConnector(uI,
-                        invocation.getConnectorId());
-
-                if (connector != null && connector.isConnectorEnabled()) {
-                    enabledConnectors.add(connector);
-                }
-            }
-
-            for (int i = 0; i < invocations.size(); i++) {
-                MethodInvocation invocation = invocations.get(i);
-
-                final ClientConnector connector = getConnector(uI,
-                        invocation.getConnectorId());
-                if (connector == null) {
-                    getLogger()
-                            .log(Level.WARNING,
-                                    "Received RPC call for unknown connector with id {0} (tried to invoke {1}.{2})",
-                                    new Object[] { invocation.getConnectorId(),
-                                            invocation.getInterfaceName(),
-                                            invocation.getMethodName() });
-                    continue;
-                }
-
-                if (!enabledConnectors.contains(connector)) {
-
-                    if (invocation instanceof LegacyChangeVariablesInvocation) {
-                        LegacyChangeVariablesInvocation legacyInvocation = (LegacyChangeVariablesInvocation) invocation;
-                        // TODO convert window close to a separate RPC call and
-                        // handle above - not a variable change
-
-                        // Handle special case where window-close is called
-                        // after the window has been removed from the
-                        // application or the application has closed
-                        Map<String, Object> changes = legacyInvocation
-                                .getVariableChanges();
-                        if (changes.size() == 1 && changes.containsKey("close")
-                                && Boolean.TRUE.equals(changes.get("close"))) {
-                            // Silently ignore this
-                            continue;
-                        }
-                    }
-
-                    // Connector is disabled, log a warning and move to the next
-                    String msg = "Ignoring RPC call for disabled connector "
-                            + connector.getClass().getName();
-                    if (connector instanceof Component) {
-                        String caption = ((Component) connector).getCaption();
-                        if (caption != null) {
-                            msg += ", caption=" + caption;
-                        }
-                    }
-                    getLogger().warning(msg);
-                    continue;
-                }
-
-                if (invocation instanceof ServerRpcMethodInvocation) {
-                    try {
-                        ServerRpcManager.applyInvocation(connector,
-                                (ServerRpcMethodInvocation) invocation);
-                    } catch (RpcInvocationException e) {
-                        handleConnectorRelatedException(connector, e);
-                    }
-                } else {
-
-                    // All code below is for legacy variable changes
-                    LegacyChangeVariablesInvocation legacyInvocation = (LegacyChangeVariablesInvocation) invocation;
-                    Map<String, Object> changes = legacyInvocation
-                            .getVariableChanges();
-                    try {
-                        if (connector instanceof VariableOwner) {
-                            changeVariables(source, (VariableOwner) connector,
-                                    changes);
-                        } else {
-                            throw new IllegalStateException(
-                                    "Received legacy variable change for "
-                                            + connector.getClass().getName()
-                                            + " ("
-                                            + connector.getConnectorId()
-                                            + ") which is not a VariableOwner. The client-side connector sent these legacy varaibles: "
-                                            + changes.keySet());
-                        }
-                    } catch (Exception e) {
-                        handleConnectorRelatedException(connector, e);
-                    }
-                }
-            }
-        } catch (JSONException e) {
-            getLogger().log(Level.WARNING,
-                    "Unable to parse RPC call from the client: {0}",
-                    e.getMessage());
-            // TODO or return success = false?
-            throw new RuntimeException(e);
-        }
-
-        return success;
-    }
-
-    /**
-     * Handles an exception that occurred when processing Rpc calls or a file
-     * upload.
-     * 
-     * @param ui
-     *            The UI where the exception occured
-     * @param throwable
-     *            The exception
-     * @param connector
-     *            The Rpc target
-     */
-    private void handleConnectorRelatedException(ClientConnector connector,
-            Throwable throwable) {
-        ErrorEvent errorEvent = new ConnectorErrorEvent(connector, throwable);
-        ErrorHandler handler = ErrorEvent.findErrorHandler(connector);
-        handler.error(errorEvent);
-    }
-
-    /**
-     * Parse a message burst from the client into a list of MethodInvocation
-     * instances.
-     * 
-     * @param connectorTracker
-     *            The ConnectorTracker used to lookup connectors
-     * @param burst
-     *            message string (JSON)
-     * @return list of MethodInvocation to perform
-     * @throws JSONException
+     * @deprecated As of 7.1. See #11411.
      */
-    private List<MethodInvocation> parseInvocations(
-            ConnectorTracker connectorTracker, final String burst)
-            throws JSONException {
-        JSONArray invocationsJson = new JSONArray(burst);
-
-        ArrayList<MethodInvocation> invocations = new ArrayList<MethodInvocation>();
-
-        MethodInvocation previousInvocation = null;
-        // parse JSON to MethodInvocations
-        for (int i = 0; i < invocationsJson.length(); ++i) {
-
-            JSONArray invocationJson = invocationsJson.getJSONArray(i);
-
-            MethodInvocation invocation = parseInvocation(invocationJson,
-                    previousInvocation, connectorTracker);
-            if (invocation != null) {
-                // Can be null if the invocation was a legacy invocation and it
-                // was merged with the previous one or if the invocation was
-                // rejected because of an error.
-                invocations.add(invocation);
-                previousInvocation = invocation;
-            }
-        }
-        return invocations;
-    }
-
-    private MethodInvocation parseInvocation(JSONArray invocationJson,
-            MethodInvocation previousInvocation,
-            ConnectorTracker connectorTracker) throws JSONException {
-        String connectorId = invocationJson.getString(0);
-        String interfaceName = invocationJson.getString(1);
-        String methodName = invocationJson.getString(2);
-
-        if (connectorTracker.getConnector(connectorId) == null
-                && !connectorId
-                        .equals(ApplicationConstants.DRAG_AND_DROP_CONNECTOR_ID)) {
-            getLogger()
-                    .log(Level.WARNING,
-                            "RPC call to "
-                                    + interfaceName
-                                    + "."
-                                    + methodName
-                                    + " received for connector "
-                                    + connectorId
-                                    + " but no such connector could be found. Resynchronizing client.");
-            // This is likely an out of sync issue (client tries to update a
-            // connector which is not present). Force resync.
-            connectorTracker.markAllConnectorsDirty();
-            return null;
-        }
-
-        JSONArray parametersJson = invocationJson.getJSONArray(3);
-
-        if (LegacyChangeVariablesInvocation.isLegacyVariableChange(
-                interfaceName, methodName)) {
-            if (!(previousInvocation instanceof LegacyChangeVariablesInvocation)) {
-                previousInvocation = null;
-            }
-
-            return parseLegacyChangeVariablesInvocation(connectorId,
-                    interfaceName, methodName,
-                    (LegacyChangeVariablesInvocation) previousInvocation,
-                    parametersJson, connectorTracker);
-        } else {
-            return parseServerRpcInvocation(connectorId, interfaceName,
-                    methodName, parametersJson, connectorTracker);
-        }
-
-    }
-
-    private LegacyChangeVariablesInvocation parseLegacyChangeVariablesInvocation(
-            String connectorId, String interfaceName, String methodName,
-            LegacyChangeVariablesInvocation previousInvocation,
-            JSONArray parametersJson, ConnectorTracker connectorTracker)
-            throws JSONException {
-        if (parametersJson.length() != 2) {
-            throw new JSONException(
-                    "Invalid parameters in legacy change variables call. Expected 2, was "
-                            + parametersJson.length());
-        }
-        String variableName = parametersJson.getString(0);
-        UidlValue uidlValue = (UidlValue) JsonCodec.decodeInternalType(
-                UidlValue.class, true, parametersJson.get(1), connectorTracker);
-
-        Object value = uidlValue.getValue();
-
-        if (previousInvocation != null
-                && previousInvocation.getConnectorId().equals(connectorId)) {
-            previousInvocation.setVariableChange(variableName, value);
-            return null;
-        } else {
-            return new LegacyChangeVariablesInvocation(connectorId,
-                    variableName, value);
-        }
-    }
-
-    private ServerRpcMethodInvocation parseServerRpcInvocation(
-            String connectorId, String interfaceName, String methodName,
-            JSONArray parametersJson, ConnectorTracker connectorTracker)
-            throws JSONException {
-        ClientConnector connector = connectorTracker.getConnector(connectorId);
-
-        ServerRpcManager<?> rpcManager = connector.getRpcManager(interfaceName);
-        if (rpcManager == null) {
-            /*
-             * Security: Don't even decode the json parameters if no RpcManager
-             * corresponding to the received method invocation has been
-             * registered.
-             */
-            getLogger()
-                    .log(Level.WARNING,
-                            "Ignoring RPC call to {0}.{1} in connector {2} ({3}) as no RPC implementation is regsitered",
-                            new Object[] { interfaceName, methodName,
-                                    connector.getClass().getName(), connectorId });
-            return null;
-        }
-
-        // Use interface from RpcManager instead of loading the class based on
-        // the string name to avoid problems with OSGi
-        Class<? extends ServerRpc> rpcInterface = rpcManager.getRpcInterface();
-
-        ServerRpcMethodInvocation invocation = new ServerRpcMethodInvocation(
-                connectorId, rpcInterface, methodName, parametersJson.length());
-
-        Object[] parameters = new Object[parametersJson.length()];
-        Type[] declaredRpcMethodParameterTypes = invocation.getMethod()
-                .getGenericParameterTypes();
-
-        for (int j = 0; j < parametersJson.length(); ++j) {
-            Object parameterValue = parametersJson.get(j);
-            Type parameterType = declaredRpcMethodParameterTypes[j];
-            parameters[j] = JsonCodec.decodeInternalOrCustomType(parameterType,
-                    parameterValue, connectorTracker);
-        }
-        invocation.setParameters(parameters);
-        return invocation;
-    }
-
-    protected void changeVariables(Object source, final VariableOwner owner,
-            Map<String, Object> m) {
-        owner.changeVariables(source, m);
-    }
-
-    protected ClientConnector getConnector(UI uI, String connectorId) {
+    @Deprecated
+    public ClientConnector getConnector(UI uI, String connectorId) {
         ClientConnector c = uI.getConnectorTracker().getConnector(connectorId);
         if (c == null
                 && connectorId.equals(getDragAndDropService().getConnectorId())) {
@@ -1899,7 +375,11 @@ public abstract class AbstractCommunicationManager implements Serializable {
         return c;
     }
 
-    private DragAndDropService getDragAndDropService() {
+    /**
+     * @deprecated As of 7.1. See #11409.
+     */
+    @Deprecated
+    public DragAndDropService getDragAndDropService() {
         if (dragAndDropService == null) {
             dragAndDropService = new DragAndDropService(this);
         }
@@ -1907,255 +387,17 @@ public abstract class AbstractCommunicationManager implements Serializable {
     }
 
     /**
-     * Reads the request data from the Request and returns it converted to an
-     * UTF-8 string.
-     * 
-     * @param request
-     * @return
-     * @throws IOException
-     */
-    protected String getRequestPayload(VaadinRequest request)
-            throws IOException {
-
-        int requestLength = request.getContentLength();
-        if (requestLength == 0) {
-            return null;
-        }
-
-        ByteArrayOutputStream bout = requestLength <= 0 ? new ByteArrayOutputStream()
-                : new ByteArrayOutputStream(requestLength);
-
-        InputStream inputStream = request.getInputStream();
-        byte[] buffer = new byte[MAX_BUFFER_SIZE];
-
-        while (true) {
-            int read = inputStream.read(buffer);
-            if (read == -1) {
-                break;
-            }
-            bout.write(buffer, 0, read);
-        }
-        String result = new String(bout.toByteArray(), "utf-8");
-
-        return result;
-    }
-
-    /**
-     * Unescape encoded burst separator characters in a burst received from the
-     * client. This protects from separator injection attacks.
-     * 
-     * @param encodedValue
-     *            to decode
-     * @return decoded value
-     */
-    protected String unescapeBurst(String encodedValue) {
-        final StringBuilder result = new StringBuilder();
-        final StringCharacterIterator iterator = new StringCharacterIterator(
-                encodedValue);
-        char character = iterator.current();
-        while (character != CharacterIterator.DONE) {
-            if (VAR_ESCAPE_CHARACTER == character) {
-                character = iterator.next();
-                switch (character) {
-                case VAR_ESCAPE_CHARACTER + 0x30:
-                    // escaped escape character
-                    result.append(VAR_ESCAPE_CHARACTER);
-                    break;
-                case VAR_BURST_SEPARATOR + 0x30:
-                    // +0x30 makes these letters for easier reading
-                    result.append((char) (character - 0x30));
-                    break;
-                case CharacterIterator.DONE:
-                    // error
-                    throw new RuntimeException(
-                            "Communication error: Unexpected end of message");
-                default:
-                    // other escaped character - probably a client-server
-                    // version mismatch
-                    throw new RuntimeException(
-                            "Invalid escaped character from the client - check that the widgetset and server versions match");
-                }
-            } else {
-                // not a special character - add it to the result as is
-                result.append(character);
-            }
-            character = iterator.next();
-        }
-        return result.toString();
-    }
-
-    /**
      * Prints the queued (pending) locale definitions to a {@link PrintWriter}
      * in a (UIDL) format that can be sent to the client and used there in
      * formatting dates, times etc.
      * 
-     * @param outWriter
-     */
-    private void printLocaleDeclarations(PrintWriter outWriter) {
-        /*
-         * ----------------------------- Sending Locale sensitive date
-         * -----------------------------
-         */
-
-        // Send locale informations to client
-        outWriter.print(", \"locales\":[");
-        for (; pendingLocalesIndex < locales.size(); pendingLocalesIndex++) {
-
-            final Locale l = generateLocale(locales.get(pendingLocalesIndex));
-            // Locale name
-            outWriter.print("{\"name\":\"" + l.toString() + "\",");
-
-            /*
-             * Month names (both short and full)
-             */
-            final DateFormatSymbols dfs = new DateFormatSymbols(l);
-            final String[] short_months = dfs.getShortMonths();
-            final String[] months = dfs.getMonths();
-            outWriter.print("\"smn\":[\""
-                    + // ShortMonthNames
-                    short_months[0] + "\",\"" + short_months[1] + "\",\""
-                    + short_months[2] + "\",\"" + short_months[3] + "\",\""
-                    + short_months[4] + "\",\"" + short_months[5] + "\",\""
-                    + short_months[6] + "\",\"" + short_months[7] + "\",\""
-                    + short_months[8] + "\",\"" + short_months[9] + "\",\""
-                    + short_months[10] + "\",\"" + short_months[11] + "\""
-                    + "],");
-            outWriter.print("\"mn\":[\""
-                    + // MonthNames
-                    months[0] + "\",\"" + months[1] + "\",\"" + months[2]
-                    + "\",\"" + months[3] + "\",\"" + months[4] + "\",\""
-                    + months[5] + "\",\"" + months[6] + "\",\"" + months[7]
-                    + "\",\"" + months[8] + "\",\"" + months[9] + "\",\""
-                    + months[10] + "\",\"" + months[11] + "\"" + "],");
-
-            /*
-             * Weekday names (both short and full)
-             */
-            final String[] short_days = dfs.getShortWeekdays();
-            final String[] days = dfs.getWeekdays();
-            outWriter.print("\"sdn\":[\""
-                    + // ShortDayNames
-                    short_days[1] + "\",\"" + short_days[2] + "\",\""
-                    + short_days[3] + "\",\"" + short_days[4] + "\",\""
-                    + short_days[5] + "\",\"" + short_days[6] + "\",\""
-                    + short_days[7] + "\"" + "],");
-            outWriter.print("\"dn\":[\""
-                    + // DayNames
-                    days[1] + "\",\"" + days[2] + "\",\"" + days[3] + "\",\""
-                    + days[4] + "\",\"" + days[5] + "\",\"" + days[6] + "\",\""
-                    + days[7] + "\"" + "],");
-
-            /*
-             * First day of week (0 = sunday, 1 = monday)
-             */
-            final Calendar cal = new GregorianCalendar(l);
-            outWriter.print("\"fdow\":" + (cal.getFirstDayOfWeek() - 1) + ",");
-
-            /*
-             * Date formatting (MM/DD/YYYY etc.)
-             */
-
-            DateFormat dateFormat = DateFormat.getDateTimeInstance(
-                    DateFormat.SHORT, DateFormat.SHORT, l);
-            if (!(dateFormat instanceof SimpleDateFormat)) {
-                getLogger().log(Level.WARNING,
-                        "Unable to get default date pattern for locale {0}", l);
-                dateFormat = new SimpleDateFormat();
-            }
-            final String df = ((SimpleDateFormat) dateFormat).toPattern();
-
-            int timeStart = df.indexOf("H");
-            if (timeStart < 0) {
-                timeStart = df.indexOf("h");
-            }
-            final int ampm_first = df.indexOf("a");
-            // E.g. in Korean locale AM/PM is before h:mm
-            // TODO should take that into consideration on client-side as well,
-            // now always h:mm a
-            if (ampm_first > 0 && ampm_first < timeStart) {
-                timeStart = ampm_first;
-            }
-            // Hebrew locale has time before the date
-            final boolean timeFirst = timeStart == 0;
-            String dateformat;
-            if (timeFirst) {
-                int dateStart = df.indexOf(' ');
-                if (ampm_first > dateStart) {
-                    dateStart = df.indexOf(' ', ampm_first);
-                }
-                dateformat = df.substring(dateStart + 1);
-            } else {
-                dateformat = df.substring(0, timeStart - 1);
-            }
-
-            outWriter.print("\"df\":\"" + dateformat.trim() + "\",");
-
-            /*
-             * Time formatting (24 or 12 hour clock and AM/PM suffixes)
-             */
-            final String timeformat = df.substring(timeStart, df.length());
-            /*
-             * Doesn't return second or milliseconds.
-             * 
-             * We use timeformat to determine 12/24-hour clock
-             */
-            final boolean twelve_hour_clock = timeformat.indexOf("a") > -1;
-            // TODO there are other possibilities as well, like 'h' in french
-            // (ignore them, too complicated)
-            final String hour_min_delimiter = timeformat.indexOf(".") > -1 ? "."
-                    : ":";
-            // outWriter.print("\"tf\":\"" + timeformat + "\",");
-            outWriter.print("\"thc\":" + twelve_hour_clock + ",");
-            outWriter.print("\"hmd\":\"" + hour_min_delimiter + "\"");
-            if (twelve_hour_clock) {
-                final String[] ampm = dfs.getAmPmStrings();
-                outWriter.print(",\"ampm\":[\"" + ampm[0] + "\",\"" + ampm[1]
-                        + "\"]");
-            }
-            outWriter.print("}");
-            if (pendingLocalesIndex < locales.size() - 1) {
-                outWriter.print(",");
-            }
-        }
-        outWriter.print("]"); // Close locales
-    }
-
-    protected void closeJsonMessage(PrintWriter outWriter) {
-        outWriter.print("}]");
-    }
-
-    /**
-     * Writes the opening of JSON message to be sent to client.
+     * @deprecated As of 7.1. See #11378.
      * 
      * @param outWriter
-     * @param response
-     */
-    protected void openJsonMessage(PrintWriter outWriter,
-            VaadinResponse response) {
-        // Sets the response type
-        response.setContentType("application/json; charset=UTF-8");
-        // some dirt to prevent cross site scripting
-        outWriter.print("for(;;);[{");
-    }
-
-    /**
-     * Returns dirty components which are in given window. Components in an
-     * invisible subtrees are omitted.
-     * 
-     * @param w
-     *            UI window for which dirty components is to be fetched
-     * @return
      */
-    private ArrayList<ClientConnector> getDirtyVisibleConnectors(
-            ConnectorTracker connectorTracker) {
-        ArrayList<ClientConnector> dirtyConnectors = new ArrayList<ClientConnector>();
-        for (ClientConnector c : connectorTracker.getDirtyConnectors()) {
-            if (isConnectorVisibleToClient(c)) {
-                dirtyConnectors.add(c);
-            }
-        }
-
-        return dirtyConnectors;
+    @Deprecated
+    public void printLocaleDeclarations(Writer writer) throws IOException {
+        new LocaleWriter().write(locales, writer);
     }
 
     /**
@@ -2165,15 +407,17 @@ public abstract class AbstractCommunicationManager implements Serializable {
      * the need to use the {@link Locale} class and all the framework behind it
      * on the client.
      * 
+     * @deprecated As of 7.1. See #11378.
+     * 
      * @see Locale#toString()
      * 
      * @param value
      */
+    @Deprecated
     public void requireLocale(String value) {
         if (locales == null) {
             locales = new ArrayList<String>();
             locales.add(session.getLocale().toString());
-            pendingLocalesIndex = 0;
         }
         if (!locales.contains(value)) {
             locales.add(value);
@@ -2181,32 +425,23 @@ public abstract class AbstractCommunicationManager implements Serializable {
     }
 
     /**
-     * Constructs a {@link Locale} instance to be sent to the client based on a
-     * short locale description string.
-     * 
-     * @see #requireLocale(String)
-     * 
-     * @param value
-     * @return
+     * @deprecated As of 7.1. See #11378.
      */
-    private Locale generateLocale(String value) {
-        final String[] temp = value.split("_");
-        if (temp.length == 1) {
-            return new Locale(temp[0]);
-        } else if (temp.length == 2) {
-            return new Locale(temp[0], temp[1]);
-        } else {
-            return new Locale(temp[0], temp[1], temp[2]);
-        }
+    @Deprecated
+    public void resetLocales() {
+        locales = null;
     }
 
-    protected class InvalidUIDLSecurityKeyException extends
+    /**
+     * @deprecated As of 7.1. Will be removed in the future.
+     */
+    @Deprecated
+    public static class InvalidUIDLSecurityKeyException extends
             GeneralSecurityException {
 
-        InvalidUIDLSecurityKeyException(String message) {
+        public InvalidUIDLSecurityKeyException(String message) {
             super(message);
         }
-
     }
 
     private final HashMap<Class<? extends ClientConnector>, Integer> typeToKey = new HashMap<Class<? extends ClientConnector>, Integer>();
@@ -2214,7 +449,11 @@ public abstract class AbstractCommunicationManager implements Serializable {
 
     private BootstrapHandler bootstrapHandler;
 
-    String getTagForType(Class<? extends ClientConnector> class1) {
+    /**
+     * @deprecated As of 7.1. Will be removed in the future.
+     */
+    @Deprecated
+    public String getTagForType(Class<? extends ClientConnector> class1) {
         Integer id = typeToKey.get(class1);
         if (id == null) {
             id = nextTypeKey++;
@@ -2232,8 +471,11 @@ public abstract class AbstractCommunicationManager implements Serializable {
      * to know.
      * 
      * TODO make customlayout templates (from theme) to be cached here.
+     * 
+     * @deprecated As of 7.1. See #11410.
      */
-    class ClientCache implements Serializable {
+    @Deprecated
+    public class ClientCache implements Serializable {
 
         private final Set<Object> res = new HashSet<Object>();
 
@@ -2242,7 +484,7 @@ public abstract class AbstractCommunicationManager implements Serializable {
          * @param paintable
          * @return true if the given class was added to cache
          */
-        boolean cache(Object object) {
+        public boolean cache(Object object) {
             return res.add(object);
         }
 
@@ -2252,6 +494,10 @@ public abstract class AbstractCommunicationManager implements Serializable {
 
     }
 
+    /**
+     * @deprecated As of 7.1. See #11411.
+     */
+    @Deprecated
     public String getStreamVariableTargetUrl(ClientConnector owner,
             String name, StreamVariable value) {
         /*
@@ -2280,11 +526,6 @@ public abstract class AbstractCommunicationManager implements Serializable {
 
     }
 
-    public void cleanStreamVariable(ClientConnector owner, String name) {
-        owner.getUI().getConnectorTracker()
-                .cleanStreamVariable(owner.getConnectorId(), name);
-    }
-
     /**
      * Gets the bootstrap handler that should be used for generating the pages
      * bootstrapping applications for this communication manager.
@@ -2335,7 +576,10 @@ public abstract class AbstractCommunicationManager implements Serializable {
      * @see RequestHandler
      * 
      * @since 7.0
+     * 
+     * @deprecated As of 7.1. Should be moved to VaadinService.
      */
+    @Deprecated
     protected boolean handleOtherRequest(VaadinRequest request,
             VaadinResponse response) throws IOException {
         // Use a copy to avoid ConcurrentModificationException
@@ -2349,530 +593,44 @@ public abstract class AbstractCommunicationManager implements Serializable {
         return false;
     }
 
-    public void handleBrowserDetailsRequest(VaadinRequest request,
-            VaadinResponse response, VaadinSession session) throws IOException {
-
-        session.lock();
-
-        try {
-            assert UI.getCurrent() == null;
-
-            response.setContentType("application/json; charset=UTF-8");
-
-            UI uI = getBrowserDetailsUI(request, session);
-
-            JSONObject params = new JSONObject();
-            params.put(UIConstants.UI_ID_PARAMETER, uI.getUIId());
-            String initialUIDL = getInitialUIDL(request, uI);
-            params.put("uidl", initialUIDL);
-
-            // NOTE! GateIn requires, for some weird reason, getOutputStream
-            // to be used instead of getWriter() (it seems to interpret
-            // application/json as a binary content type)
-            final OutputStream out = response.getOutputStream();
-            final PrintWriter outWriter = new PrintWriter(new BufferedWriter(
-                    new OutputStreamWriter(out, "UTF-8")));
-
-            outWriter.write(params.toString());
-            // NOTE GateIn requires the buffers to be flushed to work
-            outWriter.flush();
-            out.flush();
-        } catch (JSONException e) {
-            // TODO Auto-generated catch block
-            e.printStackTrace();
-        } finally {
-            session.unlock();
-        }
-    }
-
-    private UI getBrowserDetailsUI(VaadinRequest request, VaadinSession session) {
-        VaadinService vaadinService = request.getService();
-
-        List<UIProvider> uiProviders = session.getUIProviders();
-
-        UIClassSelectionEvent classSelectionEvent = new UIClassSelectionEvent(
-                request);
-
-        UIProvider provider = null;
-        Class<? extends UI> uiClass = null;
-        for (UIProvider p : uiProviders) {
-            // Check for existing LegacyWindow
-            if (p instanceof LegacyApplicationUIProvider) {
-                LegacyApplicationUIProvider legacyProvider = (LegacyApplicationUIProvider) p;
-
-                UI existingUi = legacyProvider
-                        .getExistingUI(classSelectionEvent);
-                if (existingUi != null) {
-                    reinitUI(existingUi, request);
-                    return existingUi;
-                }
-            }
-
-            uiClass = p.getUIClass(classSelectionEvent);
-            if (uiClass != null) {
-                provider = p;
-                break;
-            }
-        }
-
-        if (provider == null || uiClass == null) {
-            return null;
-        }
-
-        // Check for an existing UI based on window.name
-
-        // Special parameter sent by vaadinBootstrap.js
-        String windowName = request.getParameter("v-wn");
-
-        Map<String, Integer> retainOnRefreshUIs = session
-                .getPreserveOnRefreshUIs();
-        if (windowName != null && !retainOnRefreshUIs.isEmpty()) {
-            // Check for a known UI
-
-            Integer retainedUIId = retainOnRefreshUIs.get(windowName);
-
-            if (retainedUIId != null) {
-                UI retainedUI = session.getUIById(retainedUIId.intValue());
-                if (uiClass.isInstance(retainedUI)) {
-                    reinitUI(retainedUI, request);
-                    return retainedUI;
-                } else {
-                    getLogger().log(
-                            Level.INFO,
-                            "Not using retained UI in {0} because retained UI was of type {1}"
-                                    + " but {2} is expected for the request.",
-                            new Object[] { windowName, retainedUI.getClass(),
-                                    uiClass });
-                }
-            }
-        }
-
-        // No existing UI found - go on by creating and initializing one
-
-        Integer uiId = Integer.valueOf(session.getNextUIid());
-
-        // Explicit Class.cast to detect if the UIProvider does something
-        // unexpected
-        UICreateEvent event = new UICreateEvent(request, uiClass, uiId);
-        UI ui = uiClass.cast(provider.createInstance(event));
-
-        // Initialize some fields for a newly created UI
-        if (ui.getSession() != session) {
-            // Session already set for LegacyWindow
-            ui.setSession(session);
-        }
-
-        // Set thread local here so it is available in init
-        UI.setCurrent(ui);
-
-        ui.doInit(request, uiId.intValue());
-
-        session.addUI(ui);
-
-        // Remember if it should be remembered
-        if (vaadinService.preserveUIOnRefresh(provider, event)) {
-            // Remember this UI
-            if (windowName == null) {
-                getLogger()
-                        .log(Level.WARNING,
-                                "There is no window.name available for UI {0} that should be preserved.",
-                                uiClass);
-            } else {
-                session.getPreserveOnRefreshUIs().put(windowName, uiId);
-            }
-        }
-
-        return ui;
-    }
-
-    /**
-     * Updates a UI that has already been initialized but is now loaded again,
-     * e.g. because of {@link PreserveOnRefresh}.
-     * 
-     * @param ui
-     * @param request
-     */
-    private void reinitUI(UI ui, VaadinRequest request) {
-        UI.setCurrent(ui);
-
-        // Fire fragment change if the fragment has changed
-        String location = request.getParameter("v-loc");
-        if (location != null) {
-            ui.getPage().updateLocation(location);
-        }
-    }
-
     /**
-     * Generates the initial UIDL message that can e.g. be included in a html
-     * page to avoid a separate round trip just for getting the UIDL.
-     * 
-     * @param request
-     *            the request that caused the initialization
-     * @param uI
-     *            the UI for which the UIDL should be generated
-     * @return a string with the initial UIDL message
-     * @throws PaintException
-     *             if an exception occurs while painting
-     * @throws JSONException
-     *             if an exception occurs while encoding output
-     */
-    protected String getInitialUIDL(VaadinRequest request, UI uI)
-            throws PaintException, JSONException {
-        // TODO maybe unify writeUidlResponse()?
-        StringWriter sWriter = new StringWriter();
-        PrintWriter pWriter = new PrintWriter(sWriter);
-        pWriter.print("{");
-        if (isXSRFEnabled(uI.getSession())) {
-            pWriter.print(getSecurityKeyUIDL(request));
-        }
-        writeUidlResponse(request, true, pWriter, uI, false);
-        pWriter.print("}");
-        String initialUIDL = sWriter.toString();
-        getLogger().log(Level.FINE, "Initial UIDL:{0}", initialUIDL);
-        return initialUIDL;
-    }
-
-    /**
-     * Serve a connector resource from the classpath if the resource has
-     * previously been registered by calling
-     * {@link #registerPublishedFile(String, Class)}. Sending arbitrary files
-     * from the classpath is prevented by only accepting resource names that
-     * have explicitly been registered. Resources can currently only be
-     * registered by including a {@link JavaScript} or {@link StyleSheet}
-     * annotation on a Connector class.
-     * 
-     * @param request
-     * @param response
-     * 
-     * @throws IOException
-     */
-    public void servePublishedFile(VaadinRequest request,
-            VaadinResponse response) throws IOException {
-
-        String pathInfo = request.getPathInfo();
-        // + 2 to also remove beginning and ending slashes
-        String fileName = pathInfo
-                .substring(ApplicationConstants.PUBLISHED_FILE_PATH.length() + 2);
-
-        final String mimetype = response.getService().getMimeType(fileName);
-
-        // Security check: avoid accidentally serving from the UI of the
-        // classpath instead of relative to the context class
-        if (fileName.startsWith("/")) {
-            getLogger().log(Level.WARNING,
-                    "Published file request starting with / rejected: {0}",
-                    fileName);
-            response.sendError(HttpServletResponse.SC_NOT_FOUND, fileName);
-            return;
-        }
-
-        // Check that the resource name has been registered
-        Class<?> context;
-        synchronized (publishedFileContexts) {
-            context = publishedFileContexts.get(fileName);
-        }
-
-        // Security check: don't serve resource if the name hasn't been
-        // registered in the map
-        if (context == null) {
-            getLogger()
-                    .log(Level.WARNING,
-                            "Rejecting published file request for file that has not been published: {0}",
-                            fileName);
-            response.sendError(HttpServletResponse.SC_NOT_FOUND, fileName);
-            return;
-        }
-
-        // Resolve file relative to the location of the context class
-        InputStream in = context.getResourceAsStream(fileName);
-        if (in == null) {
-            getLogger()
-                    .log(Level.WARNING,
-                            "{0} published by {1} not found. Verify that the file {2}/{3} is available on the classpath.",
-                            new Object[] {
-                                    fileName,
-                                    context.getName(),
-                                    context.getPackage().getName()
-                                            .replace('.', '/'), fileName });
-            response.sendError(HttpServletResponse.SC_NOT_FOUND, fileName);
-            return;
-        }
-
-        // TODO Check and set cache headers
-
-        OutputStream out = null;
-        try {
-            if (mimetype != null) {
-                response.setContentType(mimetype);
-            }
-
-            out = response.getOutputStream();
-
-            final byte[] buffer = new byte[Constants.DEFAULT_BUFFER_SIZE];
-
-            int bytesRead = 0;
-            while ((bytesRead = in.read(buffer)) > 0) {
-                out.write(buffer, 0, bytesRead);
-            }
-            out.flush();
-        } finally {
-            try {
-                in.close();
-            } catch (Exception e) {
-                // Do nothing
-            }
-            if (out != null) {
-                try {
-                    out.close();
-                } catch (Exception e) {
-                    // Do nothing
-                }
-            }
-        }
-    }
-
-    /**
-     * Handles file upload request submitted via Upload component.
-     * 
-     * @param UI
-     *            The UI for this request
+     * Handles an exception that occurred when processing RPC calls or a file
+     * upload.
      * 
-     * @see #getStreamVariableTargetUrl(ReceiverOwner, String, StreamVariable)
+     * @deprecated As of 7.1. See #11411.
      * 
-     * @param request
-     * @param response
-     * @throws IOException
-     * @throws InvalidUIDLSecurityKeyException
-     */
-    public void handleFileUpload(VaadinSession session, VaadinRequest request,
-            VaadinResponse response) throws IOException,
-            InvalidUIDLSecurityKeyException {
-
-        /*
-         * URI pattern: APP/UPLOAD/[UIID]/[PID]/[NAME]/[SECKEY] See
-         * #createReceiverUrl
-         */
-
-        String pathInfo = request.getPathInfo();
-        // strip away part until the data we are interested starts
-        int startOfData = pathInfo
-                .indexOf(ServletPortletHelper.UPLOAD_URL_PREFIX)
-                + ServletPortletHelper.UPLOAD_URL_PREFIX.length();
-        String uppUri = pathInfo.substring(startOfData);
-        String[] parts = uppUri.split("/", 4); // 0= UIid, 1 = cid, 2= name, 3
-                                               // = sec key
-        String uiId = parts[0];
-        String connectorId = parts[1];
-        String variableName = parts[2];
-        UI uI = session.getUIById(Integer.parseInt(uiId));
-        UI.setCurrent(uI);
-
-        StreamVariable streamVariable = uI.getConnectorTracker()
-                .getStreamVariable(connectorId, variableName);
-        String secKey = uI.getConnectorTracker().getSeckey(streamVariable);
-        if (secKey.equals(parts[3])) {
-
-            ClientConnector source = getConnector(uI, connectorId);
-            String contentType = request.getContentType();
-            if (contentType.contains("boundary")) {
-                // Multipart requests contain boundary string
-                doHandleSimpleMultipartFileUpload(request, response,
-                        streamVariable, variableName, source,
-                        contentType.split("boundary=")[1]);
-            } else {
-                // if boundary string does not exist, the posted file is from
-                // XHR2.post(File)
-                doHandleXhrFilePost(request, response, streamVariable,
-                        variableName, source, request.getContentLength());
-            }
-        } else {
-            throw new InvalidUIDLSecurityKeyException(
-                    "Security key in upload post did not match!");
-        }
-
-    }
-
-    /**
-     * Handles a heartbeat request. Heartbeat requests are periodically sent by
-     * the client-side to inform the server that the UI sending the heartbeat is
-     * still alive (the browser window is open, the connection is up) even when
-     * there are no UIDL requests for a prolonged period of time. UIs that do
-     * not receive either heartbeat or UIDL requests are eventually removed from
-     * the session and garbage collected.
-     * 
-     * @param request
-     * @param response
-     * @param session
-     * @throws IOException
+     * @param ui
+     *            The UI where the exception occured
+     * @param throwable
+     *            The exception
+     * @param connector
+     *            The Rpc target
      */
-    public void handleHeartbeatRequest(VaadinRequest request,
-            VaadinResponse response, VaadinSession session) throws IOException {
-        UI ui = null;
-        try {
-            int uiId = Integer.parseInt(request
-                    .getParameter(UIConstants.UI_ID_PARAMETER));
-            ui = session.getUIById(uiId);
-        } catch (NumberFormatException nfe) {
-            // null-check below handles this as well
-        }
-        if (ui != null) {
-            ui.setLastHeartbeatTimestamp(System.currentTimeMillis());
-            // Ensure that the browser does not cache heartbeat responses.
-            // iOS 6 Safari requires this (#10370)
-            response.setHeader("Cache-Control", "no-cache");
-        } else {
-            response.sendError(HttpServletResponse.SC_NOT_FOUND, "UI not found");
-        }
+    @Deprecated
+    public void handleConnectorRelatedException(ClientConnector connector,
+            Throwable throwable) {
+        ErrorEvent errorEvent = new ConnectorErrorEvent(connector, throwable);
+        ErrorHandler handler = ErrorEvent.findErrorHandler(connector);
+        handler.error(errorEvent);
     }
 
     /**
-     * Stream that extracts content from another stream until the boundary
-     * string is encountered.
+     * Requests that the given UI should be fully re-rendered on the client
+     * side.
      * 
-     * Public only for unit tests, should be considered private for all other
-     * purposes.
+     * @since 7.1
+     * @deprecated. As of 7.1. Should be refactored once locales are fixed
+     *              (#11378)
      */
-    public static class SimpleMultiPartInputStream extends InputStream {
-
-        /**
-         * Counter of how many characters have been matched to boundary string
-         * from the stream
-         */
-        int matchedCount = -1;
-
-        /**
-         * Used as pointer when returning bytes after partly matched boundary
-         * string.
-         */
-        int curBoundaryIndex = 0;
-        /**
-         * The byte found after a "promising start for boundary"
-         */
-        private int bufferedByte = -1;
-        private boolean atTheEnd = false;
-
-        private final char[] boundary;
-
-        private final InputStream realInputStream;
-
-        public SimpleMultiPartInputStream(InputStream realInputStream,
-                String boundaryString) {
-            boundary = (CRLF + DASHDASH + boundaryString).toCharArray();
-            this.realInputStream = realInputStream;
-        }
-
-        @Override
-        public int read() throws IOException {
-            if (atTheEnd) {
-                // End boundary reached, nothing more to read
-                return -1;
-            } else if (bufferedByte >= 0) {
-                /* Purge partially matched boundary if there was such */
-                return getBuffered();
-            } else if (matchedCount != -1) {
-                /*
-                 * Special case where last "failed" matching ended with first
-                 * character from boundary string
-                 */
-                return matchForBoundary();
-            } else {
-                int fromActualStream = realInputStream.read();
-                if (fromActualStream == -1) {
-                    // unexpected end of stream
-                    throw new IOException(
-                            "The multipart stream ended unexpectedly");
-                }
-                if (boundary[0] == fromActualStream) {
-                    /*
-                     * If matches the first character in boundary string, start
-                     * checking if the boundary is fetched.
-                     */
-                    return matchForBoundary();
-                }
-                return fromActualStream;
-            }
-        }
-
-        /**
-         * Reads the input to expect a boundary string. Expects that the first
-         * character has already been matched.
-         * 
-         * @return -1 if the boundary was matched, else returns the first byte
-         *         from boundary
-         * @throws IOException
-         */
-        private int matchForBoundary() throws IOException {
-            matchedCount = 0;
-            /*
-             * Going to "buffered mode". Read until full boundary match or a
-             * different character.
-             */
-            while (true) {
-                matchedCount++;
-                if (matchedCount == boundary.length) {
-                    /*
-                     * The whole boundary matched so we have reached the end of
-                     * file
-                     */
-                    atTheEnd = true;
-                    return -1;
-                }
-                int fromActualStream = realInputStream.read();
-                if (fromActualStream != boundary[matchedCount]) {
-                    /*
-                     * Did not find full boundary, cache the mismatching byte
-                     * and start returning the partially matched boundary.
-                     */
-                    bufferedByte = fromActualStream;
-                    return getBuffered();
-                }
-            }
-        }
+    @Deprecated
+    public void repaintAll(UI ui) {
+        getClientCache(ui).clear();
+        ui.getConnectorTracker().markAllConnectorsDirty();
+        ui.getConnectorTracker().markAllClientSidesUninitialized();
 
-        /**
-         * Returns the partly matched boundary string and the byte following
-         * that.
-         * 
-         * @return
-         * @throws IOException
-         */
-        private int getBuffered() throws IOException {
-            int b;
-            if (matchedCount == 0) {
-                // The boundary has been returned, return the buffered byte.
-                b = bufferedByte;
-                bufferedByte = -1;
-                matchedCount = -1;
-            } else {
-                b = boundary[curBoundaryIndex++];
-                if (curBoundaryIndex == matchedCount) {
-                    // The full boundary has been returned, remaining is the
-                    // char that did not match the boundary.
-
-                    curBoundaryIndex = 0;
-                    if (bufferedByte != boundary[0]) {
-                        /*
-                         * next call for getBuffered will return the
-                         * bufferedByte that came after the partial boundary
-                         * match
-                         */
-                        matchedCount = 0;
-                    } else {
-                        /*
-                         * Special case where buffered byte again matches the
-                         * boundaryString. This could be the start of the real
-                         * end boundary.
-                         */
-                        matchedCount = 0;
-                        bufferedByte = -1;
-                    }
-                }
-            }
-            if (b == -1) {
-                throw new IOException("The multipart stream ended unexpectedly");
-            }
-            return b;
-        }
+        // Reset sent locales
+        resetLocales();
+        requireLocale(session.getLocale().toString());
     }
 
     private static final Logger getLogger() {
diff --git a/server/src/com/vaadin/server/CommunicationManager.java b/server/src/com/vaadin/server/CommunicationManager.java
index 8b3550481d..44e8f87d9f 100644
--- a/server/src/com/vaadin/server/CommunicationManager.java
+++ b/server/src/com/vaadin/server/CommunicationManager.java
@@ -80,7 +80,7 @@ public class CommunicationManager extends AbstractCommunicationManager {
     }
 
     @Override
-    protected InputStream getThemeResourceAsStream(UI uI, String themeName,
+    public InputStream getThemeResourceAsStream(UI uI, String themeName,
             String resource) {
         VaadinServletService service = (VaadinServletService) uI.getSession()
                 .getService();
diff --git a/server/src/com/vaadin/server/ComponentSizeValidator.java b/server/src/com/vaadin/server/ComponentSizeValidator.java
index f5e2e2fe12..27d087a2b2 100644
--- a/server/src/com/vaadin/server/ComponentSizeValidator.java
+++ b/server/src/com/vaadin/server/ComponentSizeValidator.java
@@ -191,7 +191,6 @@ public class ComponentSizeValidator implements Serializable {
         }
 
         public void reportErrors(PrintWriter clientJSON,
-                AbstractCommunicationManager communicationManager,
                 PrintStream serverErrorStream) {
             clientJSON.write("{");
 
@@ -269,8 +268,7 @@ public class ComponentSizeValidator implements Serializable {
                     } else {
                         first = false;
                     }
-                    subError.reportErrors(clientJSON, communicationManager,
-                            serverErrorStream);
+                    subError.reportErrors(clientJSON, serverErrorStream);
                 }
                 clientJSON.write("]");
                 serverErrorStream.println("<< Sub erros");
diff --git a/server/src/com/vaadin/server/DragAndDropService.java b/server/src/com/vaadin/server/DragAndDropService.java
index 5a54b5ae3a..e403f4d4cb 100644
--- a/server/src/com/vaadin/server/DragAndDropService.java
+++ b/server/src/com/vaadin/server/DragAndDropService.java
@@ -16,7 +16,7 @@
 package com.vaadin.server;
 
 import java.io.IOException;
-import java.io.PrintWriter;
+import java.io.Writer;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
@@ -209,10 +209,10 @@ public class DragAndDropService implements VariableOwner, ClientConnector {
         return true;
     }
 
-    void printJSONResponse(PrintWriter outWriter) throws PaintException {
+    public void printJSONResponse(Writer outWriter) throws IOException {
         if (isDirty()) {
 
-            outWriter.print(", \"dd\":");
+            outWriter.write(", \"dd\":");
 
             JsonPaintTarget jsonPaintTarget = new JsonPaintTarget(manager,
                     outWriter, false);
diff --git a/server/src/com/vaadin/server/JsonPaintTarget.java b/server/src/com/vaadin/server/JsonPaintTarget.java
index 11bfb33fe1..35ff8659ad 100644
--- a/server/src/com/vaadin/server/JsonPaintTarget.java
+++ b/server/src/com/vaadin/server/JsonPaintTarget.java
@@ -18,6 +18,7 @@ package com.vaadin.server;
 
 import java.io.PrintWriter;
 import java.io.Serializable;
+import java.io.Writer;
 import java.util.Collection;
 import java.util.HashSet;
 import java.util.Iterator;
@@ -87,13 +88,12 @@ public class JsonPaintTarget implements PaintTarget {
      *             if the paint operation failed.
      */
     public JsonPaintTarget(AbstractCommunicationManager manager,
-            PrintWriter outWriter, boolean cachingRequired)
-            throws PaintException {
+            Writer outWriter, boolean cachingRequired) throws PaintException {
 
         this.manager = manager;
 
         // Sets the target for UIDL writing
-        uidlBuffer = outWriter;
+        uidlBuffer = new PrintWriter(outWriter);
 
         // Initialize tag-writing
         mOpenTags = new Stack<String>();
@@ -1007,7 +1007,7 @@ public class JsonPaintTarget implements PaintTarget {
         return manager.getTagForType(clientConnectorClass);
     }
 
-    Collection<Class<? extends ClientConnector>> getUsedClientConnectors() {
+    public Collection<Class<? extends ClientConnector>> getUsedClientConnectors() {
         return usedClientConnectors;
     }
 
diff --git a/server/src/com/vaadin/server/PortletCommunicationManager.java b/server/src/com/vaadin/server/PortletCommunicationManager.java
index cece75847c..fdec421741 100644
--- a/server/src/com/vaadin/server/PortletCommunicationManager.java
+++ b/server/src/com/vaadin/server/PortletCommunicationManager.java
@@ -134,7 +134,7 @@ public class PortletCommunicationManager extends AbstractCommunicationManager {
     }
 
     @Override
-    protected InputStream getThemeResourceAsStream(UI uI, String themeName,
+    public InputStream getThemeResourceAsStream(UI uI, String themeName,
             String resource) {
         VaadinPortletSession session = (VaadinPortletSession) uI.getSession();
         PortletContext portletContext = session.getPortletSession()
diff --git a/server/src/com/vaadin/server/ServerRpcManager.java b/server/src/com/vaadin/server/ServerRpcManager.java
index ec25ce83ca..a1682cb453 100644
--- a/server/src/com/vaadin/server/ServerRpcManager.java
+++ b/server/src/com/vaadin/server/ServerRpcManager.java
@@ -139,7 +139,7 @@ public class ServerRpcManager<T extends ServerRpc> implements Serializable {
      * 
      * @return RPC interface type
      */
-    protected Class<T> getRpcInterface() {
+    public Class<T> getRpcInterface() {
         return rpcInterface;
     }
 
diff --git a/server/src/com/vaadin/server/ServletPortletHelper.java b/server/src/com/vaadin/server/ServletPortletHelper.java
index ce9872f40e..baf697cae3 100644
--- a/server/src/com/vaadin/server/ServletPortletHelper.java
+++ b/server/src/com/vaadin/server/ServletPortletHelper.java
@@ -23,23 +23,14 @@ import com.vaadin.shared.ApplicationConstants;
 import com.vaadin.ui.Component;
 import com.vaadin.ui.UI;
 
-/*
- * Copyright 2000-2013 Vaadin Ltd.
- * 
- * Licensed under the Apache License, Version 2.0 (the "License"); you may not
- * use this file except in compliance with the License. You may obtain a copy of
- * the License at
- * 
- * http://www.apache.org/licenses/LICENSE-2.0
+/**
+ * Contains helper methods shared by {@link VaadinServlet} and
+ * {@link VaadinPortlet}.
  * 
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations under
- * the License.
+ * @deprecated As of 7.1. Will be removed or refactored in the future.
  */
-
-class ServletPortletHelper implements Serializable {
+@Deprecated
+public class ServletPortletHelper implements Serializable {
     public static final String UPLOAD_URL_PREFIX = "APP/UPLOAD/";
     /**
      * The default SystemMessages (read-only).
diff --git a/server/src/com/vaadin/server/VaadinPortlet.java b/server/src/com/vaadin/server/VaadinPortlet.java
index b4a2390fa5..2abf140a3d 100644
--- a/server/src/com/vaadin/server/VaadinPortlet.java
+++ b/server/src/com/vaadin/server/VaadinPortlet.java
@@ -24,7 +24,6 @@ import java.io.PrintWriter;
 import java.io.Serializable;
 import java.lang.reflect.Method;
 import java.net.MalformedURLException;
-import java.security.GeneralSecurityException;
 import java.util.Enumeration;
 import java.util.Map;
 import java.util.Properties;
@@ -52,7 +51,12 @@ import javax.servlet.http.HttpServletResponse;
 import com.liferay.portal.kernel.util.PortalClassInvoker;
 import com.liferay.portal.kernel.util.PropsUtil;
 import com.vaadin.server.AbstractCommunicationManager.Callback;
-import com.vaadin.ui.UI;
+import com.vaadin.server.communication.FileUploadHandler;
+import com.vaadin.server.communication.HeartbeatHandler;
+import com.vaadin.server.communication.PortletListenerNotifier;
+import com.vaadin.server.communication.PublishedFileHandler;
+import com.vaadin.server.communication.UIInitHandler;
+import com.vaadin.server.communication.UidlRequestHandler;
 import com.vaadin.util.CurrentInstance;
 
 /**
@@ -422,86 +426,44 @@ public class VaadinPortlet extends GenericPortlet implements Constants,
                         return;
                     }
 
-                    PortletCommunicationManager communicationManager = (PortletCommunicationManager) vaadinSession
-                            .getCommunicationManager();
-
                     if (requestType == RequestType.PUBLISHED_FILE) {
-                        communicationManager.servePublishedFile(vaadinRequest,
-                                vaadinResponse);
+                        new PublishedFileHandler().handleRequest(vaadinSession,
+                                vaadinRequest, vaadinResponse);
                         return;
                     } else if (requestType == RequestType.HEARTBEAT) {
-                        communicationManager.handleHeartbeatRequest(
-                                vaadinRequest, vaadinResponse, vaadinSession);
+                        new HeartbeatHandler().handleRequest(vaadinSession,
+                                vaadinRequest, vaadinResponse);
                         return;
                     }
 
-                    /* Update browser information from request */
-                    vaadinSession.getBrowser().updateRequestDetails(
-                            vaadinRequest);
-
-                    /* Notify listeners */
-
-                    // Finds the right UI
-                    UI uI = null;
-                    if (requestType == RequestType.UIDL) {
-                        uI = getService().findUI(vaadinRequest);
-                    }
-
-                    // TODO Should this happen before or after the transaction
-                    // starts?
-                    if (request instanceof RenderRequest) {
-                        vaadinSession.firePortletRenderRequest(uI,
-                                (RenderRequest) request,
-                                (RenderResponse) response);
-                    } else if (request instanceof ActionRequest) {
-                        vaadinSession.firePortletActionRequest(uI,
-                                (ActionRequest) request,
-                                (ActionResponse) response);
-                    } else if (request instanceof EventRequest) {
-                        vaadinSession.firePortletEventRequest(uI,
-                                (EventRequest) request,
-                                (EventResponse) response);
-                    } else if (request instanceof ResourceRequest) {
-                        vaadinSession.firePortletResourceRequest(uI,
-                                (ResourceRequest) request,
-                                (ResourceResponse) response);
-                    }
+                    // Notify listeners
+                    new PortletListenerNotifier().handleRequest(vaadinSession,
+                            vaadinRequest, vaadinResponse);
 
                     /* Handle the request */
                     if (requestType == RequestType.FILE_UPLOAD) {
-                        // UI is resolved in handleFileUpload by
-                        // PortletCommunicationManager
-                        communicationManager.handleFileUpload(vaadinSession,
+                        new FileUploadHandler().handleRequest(vaadinSession,
                                 vaadinRequest, vaadinResponse);
                         return;
                     } else if (requestType == RequestType.BROWSER_DETAILS) {
-                        communicationManager.handleBrowserDetailsRequest(
-                                vaadinRequest, vaadinResponse, vaadinSession);
+                        new UIInitHandler().handleRequest(vaadinSession,
+                                vaadinRequest, vaadinResponse);
                         return;
                     } else if (requestType == RequestType.UIDL) {
                         // Handles AJAX UIDL requests
-                        communicationManager.handleUidlRequest(vaadinRequest,
-                                vaadinResponse, portletWrapper, uI);
+                        new UidlRequestHandler(portletWrapper).handleRequest(
+                                vaadinSession, vaadinRequest, vaadinResponse);
 
-                        // Ensure that the browser does not cache UIDL
-                        // responses.
-                        // iOS 6 Safari requires this (#9732)
-                        response.setProperty("Cache-Control", "no-cache");
                         return;
                     } else {
                         handleOtherRequest(vaadinRequest, vaadinResponse,
                                 requestType, vaadinSession,
-                                communicationManager);
+                                vaadinSession.getCommunicationManager());
                     }
                 } catch (final SessionExpiredException e) {
                     // TODO Figure out a better way to deal with
                     // SessionExpiredExceptions
                     getLogger().finest("A user session has expired");
-                } catch (final GeneralSecurityException e) {
-                    // TODO Figure out a better way to deal with
-                    // GeneralSecurityExceptions
-                    getLogger()
-                            .fine("General security exception, the security key was probably incorrect.");
                 } catch (final Throwable e) {
                     handleServiceException(vaadinRequest, vaadinResponse,
                             vaadinSession, e);
@@ -566,7 +528,7 @@ public class VaadinPortlet extends GenericPortlet implements Constants,
     private void handleOtherRequest(VaadinPortletRequest request,
             VaadinResponse response, RequestType requestType,
             VaadinSession vaadinSession,
-            PortletCommunicationManager communicationManager)
+            AbstractCommunicationManager communicationManager)
             throws PortletException, IOException, MalformedURLException {
         if (requestType == RequestType.APP || requestType == RequestType.RENDER) {
             if (!communicationManager.handleOtherRequest(request, response)) {
diff --git a/server/src/com/vaadin/server/VaadinServlet.java b/server/src/com/vaadin/server/VaadinServlet.java
index 11a7439c66..fefa8699e1 100644
--- a/server/src/com/vaadin/server/VaadinServlet.java
+++ b/server/src/com/vaadin/server/VaadinServlet.java
@@ -24,7 +24,6 @@ import java.io.PrintWriter;
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.net.URLConnection;
-import java.security.GeneralSecurityException;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Enumeration;
@@ -35,15 +34,18 @@ import java.util.logging.Logger;
 
 import javax.servlet.ServletContext;
 import javax.servlet.ServletException;
-import javax.servlet.ServletOutputStream;
 import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
 import com.vaadin.sass.internal.ScssStylesheet;
 import com.vaadin.server.AbstractCommunicationManager.Callback;
+import com.vaadin.server.communication.FileUploadHandler;
+import com.vaadin.server.communication.HeartbeatHandler;
+import com.vaadin.server.communication.PublishedFileHandler;
+import com.vaadin.server.communication.UIInitHandler;
+import com.vaadin.server.communication.UidlRequestHandler;
 import com.vaadin.shared.ApplicationConstants;
-import com.vaadin.ui.UI;
 import com.vaadin.util.CurrentInstance;
 
 @SuppressWarnings("serial")
@@ -285,49 +287,29 @@ public class VaadinServlet extends HttpServlet implements Constants {
                 return;
             }
 
-            CommunicationManager communicationManager = (CommunicationManager) vaadinSession
-                    .getCommunicationManager();
-
             if (requestType == RequestType.PUBLISHED_FILE) {
-                communicationManager.servePublishedFile(request, response);
+                new PublishedFileHandler().handleRequest(vaadinSession,
+                        request, response);
                 return;
             } else if (requestType == RequestType.HEARTBEAT) {
-                communicationManager.handleHeartbeatRequest(request, response,
-                        vaadinSession);
+                new HeartbeatHandler().handleRequest(vaadinSession, request,
+                        response);
                 return;
-            }
-
-            /* Update browser information from the request */
-            vaadinSession.getBrowser().updateRequestDetails(request);
-
-            /* Handle the request */
-            if (requestType == RequestType.FILE_UPLOAD) {
-                // UI is resolved in communication manager
-                communicationManager.handleFileUpload(vaadinSession, request,
+            } else if (requestType == RequestType.FILE_UPLOAD) {
+                new FileUploadHandler().handleRequest(vaadinSession, request,
                         response);
                 return;
             } else if (requestType == RequestType.UIDL) {
-                UI uI = getService().findUI(request);
-                if (uI == null) {
-                    throw new ServletException(ERROR_NO_UI_FOUND);
-                }
-                // Handles AJAX UIDL requests
-                communicationManager.handleUidlRequest(request, response,
-                        servletWrapper, uI);
-
-                // Ensure that the browser does not cache UIDL responses.
-                // iOS 6 Safari requires this (#9732)
-                response.setHeader("Cache-Control", "no-cache");
-
+                new UidlRequestHandler(servletWrapper).handleRequest(
+                        vaadinSession, request, response);
                 return;
             } else if (requestType == RequestType.BROWSER_DETAILS) {
                 // Browser details - not related to a specific UI
-                communicationManager.handleBrowserDetailsRequest(request,
-                        response, vaadinSession);
+                new UIInitHandler().handleRequest(vaadinSession, request,
+                        response);
                 return;
-            }
-
-            if (communicationManager.handleOtherRequest(request, response)) {
+            } else if (vaadinSession.getCommunicationManager()
+                    .handleOtherRequest(request, response)) {
                 return;
             }
 
@@ -337,8 +319,6 @@ public class VaadinServlet extends HttpServlet implements Constants {
         } catch (final SessionExpiredException e) {
             // Session has expired, notify user
             handleServiceSessionExpired(request, response);
-        } catch (final GeneralSecurityException e) {
-            handleServiceSecurityException(request, response);
         } catch (final Throwable e) {
             handleServiceException(request, response, vaadinSession, e);
         } finally {
@@ -442,7 +422,7 @@ public class VaadinServlet extends HttpServlet implements Constants {
      */
     @Deprecated
     protected void criticalNotification(VaadinServletRequest request,
-            HttpServletResponse response, String caption, String message,
+            VaadinServletResponse response, String caption, String message,
             String details, String url) throws IOException {
 
         if (ServletPortletHelper.isUIDLRequest(request)) {
@@ -493,9 +473,7 @@ public class VaadinServlet extends HttpServlet implements Constants {
                 output += "</a>";
             }
             writeResponse(response, "text/html; charset=UTF-8", output);
-
         }
-
     }
 
     /**
@@ -511,7 +489,7 @@ public class VaadinServlet extends HttpServlet implements Constants {
     private void writeResponse(HttpServletResponse response,
             String contentType, String output) throws IOException {
         response.setContentType(contentType);
-        final ServletOutputStream out = response.getOutputStream();
+        final OutputStream out = response.getOutputStream();
         // Set the response type
         final PrintWriter outWriter = new PrintWriter(new BufferedWriter(
                 new OutputStreamWriter(out, "UTF-8")));
diff --git a/server/src/com/vaadin/server/WebBrowser.java b/server/src/com/vaadin/server/WebBrowser.java
index 4122f053ae..28b92e28b8 100644
--- a/server/src/com/vaadin/server/WebBrowser.java
+++ b/server/src/com/vaadin/server/WebBrowser.java
@@ -413,7 +413,7 @@ public class WebBrowser implements Serializable {
      * @param request
      *            the Vaadin request to read the information from
      */
-    void updateRequestDetails(VaadinRequest request) {
+    public void updateRequestDetails(VaadinRequest request) {
         locale = request.getLocale();
         address = request.getRemoteAddr();
         secureConnection = request.isSecure();
diff --git a/server/src/com/vaadin/server/AbstractStreamingEvent.java b/server/src/com/vaadin/server/communication/AbstractStreamingEvent.java
index b7bf4e042f..054bc14f2d 100644
--- a/server/src/com/vaadin/server/AbstractStreamingEvent.java
+++ b/server/src/com/vaadin/server/communication/AbstractStreamingEvent.java
@@ -13,8 +13,9 @@
  * License for the specific language governing permissions and limitations under
  * the License.
  */
-package com.vaadin.server;
+package com.vaadin.server.communication;
 
+import com.vaadin.server.StreamVariable;
 import com.vaadin.server.StreamVariable.StreamingEvent;
 
 /**
diff --git a/server/src/com/vaadin/server/communication/ClientRpcWriter.java b/server/src/com/vaadin/server/communication/ClientRpcWriter.java
new file mode 100644
index 0000000000..285adac7a5
--- /dev/null
+++ b/server/src/com/vaadin/server/communication/ClientRpcWriter.java
@@ -0,0 +1,141 @@
+/*
+ * Copyright 2000-2013 Vaadin Ltd.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.vaadin.server.communication;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.io.Writer;
+import java.lang.reflect.Type;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import org.json.JSONArray;
+import org.json.JSONException;
+
+import com.vaadin.server.ClientConnector;
+import com.vaadin.server.ClientMethodInvocation;
+import com.vaadin.server.EncodeResult;
+import com.vaadin.server.JsonCodec;
+import com.vaadin.server.PaintException;
+import com.vaadin.shared.communication.ClientRpc;
+import com.vaadin.ui.UI;
+
+/**
+ * Serializes {@link ClientRpc client RPC} invocations to JSON.
+ * 
+ * @author Vaadin Ltd
+ * @since 7.1
+ */
+public class ClientRpcWriter implements Serializable {
+
+    /**
+     * Writes a JSON object containing all pending client RPC invocations in the
+     * given UI.
+     * 
+     * @param ui
+     *            The {@link UI} whose RPC calls to write.
+     * @param writer
+     *            The {@link Writer} used to write the JSON.
+     * @throws IOException
+     *             If the serialization fails.
+     */
+    public void write(UI ui, Writer writer) throws IOException {
+
+        Collection<ClientMethodInvocation> pendingInvocations = collectPendingRpcCalls(ui
+                .getConnectorTracker().getDirtyVisibleConnectors());
+
+        JSONArray rpcCalls = new JSONArray();
+        for (ClientMethodInvocation invocation : pendingInvocations) {
+            // add invocation to rpcCalls
+            try {
+                JSONArray invocationJson = new JSONArray();
+                invocationJson.put(invocation.getConnector().getConnectorId());
+                invocationJson.put(invocation.getInterfaceName());
+                invocationJson.put(invocation.getMethodName());
+                JSONArray paramJson = new JSONArray();
+                for (int i = 0; i < invocation.getParameterTypes().length; ++i) {
+                    Type parameterType = invocation.getParameterTypes()[i];
+                    Object referenceParameter = null;
+                    // TODO Use default values for RPC parameter types
+                    // if (!JsonCodec.isInternalType(parameterType)) {
+                    // try {
+                    // referenceParameter = parameterType.newInstance();
+                    // } catch (Exception e) {
+                    // logger.log(Level.WARNING,
+                    // "Error creating reference object for parameter of type "
+                    // + parameterType.getName());
+                    // }
+                    // }
+                    EncodeResult encodeResult = JsonCodec.encode(
+                            invocation.getParameters()[i], referenceParameter,
+                            parameterType, ui.getConnectorTracker());
+                    paramJson.put(encodeResult.getEncodedValue());
+                }
+                invocationJson.put(paramJson);
+                rpcCalls.put(invocationJson);
+            } catch (JSONException e) {
+                throw new PaintException(
+                        "Failed to serialize RPC method call parameters for connector "
+                                + invocation.getConnector().getConnectorId()
+                                + " method " + invocation.getInterfaceName()
+                                + "." + invocation.getMethodName() + ": "
+                                + e.getMessage(), e);
+            }
+        }
+        writer.write(rpcCalls.toString());
+    }
+
+    /**
+     * Collects all pending RPC calls from listed {@link ClientConnector}s and
+     * clears their RPC queues.
+     * 
+     * @param rpcPendingQueue
+     *            list of {@link ClientConnector} of interest
+     * @return ordered list of pending RPC calls
+     */
+    private Collection<ClientMethodInvocation> collectPendingRpcCalls(
+            Collection<ClientConnector> rpcPendingQueue) {
+        List<ClientMethodInvocation> pendingInvocations = new ArrayList<ClientMethodInvocation>();
+        for (ClientConnector connector : rpcPendingQueue) {
+            List<ClientMethodInvocation> paintablePendingRpc = connector
+                    .retrievePendingRpcCalls();
+            if (null != paintablePendingRpc && !paintablePendingRpc.isEmpty()) {
+                List<ClientMethodInvocation> oldPendingRpc = pendingInvocations;
+                int totalCalls = pendingInvocations.size()
+                        + paintablePendingRpc.size();
+                pendingInvocations = new ArrayList<ClientMethodInvocation>(
+                        totalCalls);
+
+                // merge two ordered comparable lists
+                for (int destIndex = 0, oldIndex = 0, paintableIndex = 0; destIndex < totalCalls; destIndex++) {
+                    if (paintableIndex >= paintablePendingRpc.size()
+                            || (oldIndex < oldPendingRpc.size() && ((Comparable<ClientMethodInvocation>) oldPendingRpc
+                                    .get(oldIndex))
+                                    .compareTo(paintablePendingRpc
+                                            .get(paintableIndex)) <= 0)) {
+                        pendingInvocations.add(oldPendingRpc.get(oldIndex++));
+                    } else {
+                        pendingInvocations.add(paintablePendingRpc
+                                .get(paintableIndex++));
+                    }
+                }
+            }
+        }
+        return pendingInvocations;
+    }
+}
diff --git a/server/src/com/vaadin/server/communication/ConnectorHierarchyWriter.java b/server/src/com/vaadin/server/communication/ConnectorHierarchyWriter.java
new file mode 100644
index 0000000000..0d1370528d
--- /dev/null
+++ b/server/src/com/vaadin/server/communication/ConnectorHierarchyWriter.java
@@ -0,0 +1,81 @@
+/*
+ * Copyright 2000-2013 Vaadin Ltd.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.vaadin.server.communication;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.io.Writer;
+import java.util.Collection;
+
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import com.vaadin.server.AbstractClientConnector;
+import com.vaadin.server.AbstractCommunicationManager;
+import com.vaadin.server.ClientConnector;
+import com.vaadin.server.PaintException;
+import com.vaadin.ui.UI;
+
+/**
+ * Serializes a connector hierarchy to JSON.
+ * 
+ * @author Vaadin Ltd
+ * @since 7.1
+ */
+public class ConnectorHierarchyWriter implements Serializable {
+
+    /**
+     * Writes a JSON object containing the connector hierarchy (parent-child
+     * mappings) of the dirty connectors in the given UI.
+     * 
+     * @param ui
+     *            The {@link UI} whose hierarchy to write.
+     * @param writer
+     *            The {@link Writer} used to write the JSON.
+     * @throws IOException
+     *             If the serialization fails.
+     */
+    public void write(UI ui, Writer writer) throws IOException {
+
+        Collection<ClientConnector> dirtyVisibleConnectors = ui
+                .getConnectorTracker().getDirtyVisibleConnectors();
+
+        JSONObject hierarchyInfo = new JSONObject();
+        for (ClientConnector connector : dirtyVisibleConnectors) {
+            String connectorId = connector.getConnectorId();
+            JSONArray children = new JSONArray();
+
+            for (ClientConnector child : AbstractClientConnector
+                    .getAllChildrenIterable(connector)) {
+                if (AbstractCommunicationManager
+                        .isConnectorVisibleToClient(child)) {
+                    children.put(child.getConnectorId());
+                }
+            }
+            try {
+                hierarchyInfo.put(connectorId, children);
+            } catch (JSONException e) {
+                throw new PaintException(
+                        "Failed to send hierarchy information about "
+                                + connectorId + " to the client: "
+                                + e.getMessage(), e);
+            }
+        }
+        writer.write(hierarchyInfo.toString());
+    }
+}
diff --git a/server/src/com/vaadin/server/communication/ConnectorTypeWriter.java b/server/src/com/vaadin/server/communication/ConnectorTypeWriter.java
new file mode 100644
index 0000000000..eaa1c83ff2
--- /dev/null
+++ b/server/src/com/vaadin/server/communication/ConnectorTypeWriter.java
@@ -0,0 +1,73 @@
+/*
+ * Copyright 2000-2013 Vaadin Ltd.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.vaadin.server.communication;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.io.Writer;
+import java.util.Collection;
+
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import com.vaadin.server.ClientConnector;
+import com.vaadin.server.PaintException;
+import com.vaadin.server.PaintTarget;
+import com.vaadin.ui.UI;
+
+/**
+ * Serializes connector type mappings to JSON.
+ * 
+ * @author Vaadin Ltd
+ * @since 7.1
+ */
+public class ConnectorTypeWriter implements Serializable {
+
+    /**
+     * Writes a JSON object containing connector-ID-to-type-ID mappings for each
+     * dirty Connector in the given UI.
+     * 
+     * @param ui
+     *            The {@link UI} containing dirty connectors
+     * @param writer
+     *            The {@link Writer} used to write the JSON.
+     * @param target
+     *            The paint target containing the connector type IDs.
+     * @throws IOException
+     *             If the serialization fails.
+     */
+    public void write(UI ui, Writer writer, PaintTarget target)
+            throws IOException {
+
+        Collection<ClientConnector> dirtyVisibleConnectors = ui
+                .getConnectorTracker().getDirtyVisibleConnectors();
+
+        JSONObject connectorTypes = new JSONObject();
+        for (ClientConnector connector : dirtyVisibleConnectors) {
+            String connectorType = target.getTag(connector);
+            try {
+                connectorTypes.put(connector.getConnectorId(), connectorType);
+            } catch (JSONException e) {
+                throw new PaintException(
+                        "Failed to send connector type for connector "
+                                + connector.getConnectorId() + ": "
+                                + e.getMessage(), e);
+            }
+        }
+        writer.write(connectorTypes.toString());
+    }
+}
diff --git a/server/src/com/vaadin/server/communication/FileUploadHandler.java b/server/src/com/vaadin/server/communication/FileUploadHandler.java
new file mode 100644
index 0000000000..444e0c64cd
--- /dev/null
+++ b/server/src/com/vaadin/server/communication/FileUploadHandler.java
@@ -0,0 +1,586 @@
+/*
+ * Copyright 2000-2013 Vaadin Ltd.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.vaadin.server.communication;
+
+import java.io.BufferedWriter;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.io.OutputStreamWriter;
+import java.io.PrintWriter;
+
+import com.vaadin.server.ClientConnector;
+import com.vaadin.server.NoInputStreamException;
+import com.vaadin.server.NoOutputStreamException;
+import com.vaadin.server.RequestHandler;
+import com.vaadin.server.ServletPortletHelper;
+import com.vaadin.server.StreamVariable;
+import com.vaadin.server.StreamVariable.StreamingEndEvent;
+import com.vaadin.server.StreamVariable.StreamingErrorEvent;
+import com.vaadin.server.UploadException;
+import com.vaadin.server.VaadinRequest;
+import com.vaadin.server.VaadinResponse;
+import com.vaadin.server.VaadinSession;
+import com.vaadin.ui.Component;
+import com.vaadin.ui.UI;
+
+/**
+ * Handles a file upload request submitted via an Upload component.
+ * 
+ * @author Vaadin Ltd
+ * @since 7.1
+ */
+public class FileUploadHandler implements RequestHandler {
+
+    /**
+     * Stream that extracts content from another stream until the boundary
+     * string is encountered.
+     * 
+     * Public only for unit tests, should be considered private for all other
+     * purposes.
+     */
+    public static class SimpleMultiPartInputStream extends InputStream {
+
+        /**
+         * Counter of how many characters have been matched to boundary string
+         * from the stream
+         */
+        int matchedCount = -1;
+
+        /**
+         * Used as pointer when returning bytes after partly matched boundary
+         * string.
+         */
+        int curBoundaryIndex = 0;
+        /**
+         * The byte found after a "promising start for boundary"
+         */
+        private int bufferedByte = -1;
+        private boolean atTheEnd = false;
+
+        private final char[] boundary;
+
+        private final InputStream realInputStream;
+
+        public SimpleMultiPartInputStream(InputStream realInputStream,
+                String boundaryString) {
+            boundary = (CRLF + DASHDASH + boundaryString).toCharArray();
+            this.realInputStream = realInputStream;
+        }
+
+        @Override
+        public int read() throws IOException {
+            if (atTheEnd) {
+                // End boundary reached, nothing more to read
+                return -1;
+            } else if (bufferedByte >= 0) {
+                /* Purge partially matched boundary if there was such */
+                return getBuffered();
+            } else if (matchedCount != -1) {
+                /*
+                 * Special case where last "failed" matching ended with first
+                 * character from boundary string
+                 */
+                return matchForBoundary();
+            } else {
+                int fromActualStream = realInputStream.read();
+                if (fromActualStream == -1) {
+                    // unexpected end of stream
+                    throw new IOException(
+                            "The multipart stream ended unexpectedly");
+                }
+                if (boundary[0] == fromActualStream) {
+                    /*
+                     * If matches the first character in boundary string, start
+                     * checking if the boundary is fetched.
+                     */
+                    return matchForBoundary();
+                }
+                return fromActualStream;
+            }
+        }
+
+        /**
+         * Reads the input to expect a boundary string. Expects that the first
+         * character has already been matched.
+         * 
+         * @return -1 if the boundary was matched, else returns the first byte
+         *         from boundary
+         * @throws IOException
+         */
+        private int matchForBoundary() throws IOException {
+            matchedCount = 0;
+            /*
+             * Going to "buffered mode". Read until full boundary match or a
+             * different character.
+             */
+            while (true) {
+                matchedCount++;
+                if (matchedCount == boundary.length) {
+                    /*
+                     * The whole boundary matched so we have reached the end of
+                     * file
+                     */
+                    atTheEnd = true;
+                    return -1;
+                }
+                int fromActualStream = realInputStream.read();
+                if (fromActualStream != boundary[matchedCount]) {
+                    /*
+                     * Did not find full boundary, cache the mismatching byte
+                     * and start returning the partially matched boundary.
+                     */
+                    bufferedByte = fromActualStream;
+                    return getBuffered();
+                }
+            }
+        }
+
+        /**
+         * Returns the partly matched boundary string and the byte following
+         * that.
+         * 
+         * @return
+         * @throws IOException
+         */
+        private int getBuffered() throws IOException {
+            int b;
+            if (matchedCount == 0) {
+                // The boundary has been returned, return the buffered byte.
+                b = bufferedByte;
+                bufferedByte = -1;
+                matchedCount = -1;
+            } else {
+                b = boundary[curBoundaryIndex++];
+                if (curBoundaryIndex == matchedCount) {
+                    // The full boundary has been returned, remaining is the
+                    // char that did not match the boundary.
+
+                    curBoundaryIndex = 0;
+                    if (bufferedByte != boundary[0]) {
+                        /*
+                         * next call for getBuffered will return the
+                         * bufferedByte that came after the partial boundary
+                         * match
+                         */
+                        matchedCount = 0;
+                    } else {
+                        /*
+                         * Special case where buffered byte again matches the
+                         * boundaryString. This could be the start of the real
+                         * end boundary.
+                         */
+                        matchedCount = 0;
+                        bufferedByte = -1;
+                    }
+                }
+            }
+            if (b == -1) {
+                throw new IOException("The multipart stream ended unexpectedly");
+            }
+            return b;
+        }
+    }
+
+    private static class UploadInterruptedException extends Exception {
+        public UploadInterruptedException() {
+            super("Upload interrupted by other thread");
+        }
+    }
+
+    private static final int LF = "\n".getBytes()[0];
+
+    private static final String CRLF = "\r\n";
+
+    private static final String UTF8 = "UTF-8";
+
+    private static final String DASHDASH = "--";
+
+    /* Same as in apache commons file upload library that was previously used. */
+    private static final int MAX_UPLOAD_BUFFER_SIZE = 4 * 1024;
+
+    @Override
+    public boolean handleRequest(VaadinSession session, VaadinRequest request,
+            VaadinResponse response) throws IOException {
+
+        /*
+         * URI pattern: APP/UPLOAD/[UIID]/[PID]/[NAME]/[SECKEY] See
+         * #createReceiverUrl
+         */
+
+        String pathInfo = request.getPathInfo();
+        // strip away part until the data we are interested starts
+        int startOfData = pathInfo
+                .indexOf(ServletPortletHelper.UPLOAD_URL_PREFIX)
+                + ServletPortletHelper.UPLOAD_URL_PREFIX.length();
+        String uppUri = pathInfo.substring(startOfData);
+        String[] parts = uppUri.split("/", 4); // 0= UIid, 1 = cid, 2= name, 3
+                                               // = sec key
+        String uiId = parts[0];
+        String connectorId = parts[1];
+        String variableName = parts[2];
+        UI uI = session.getUIById(Integer.parseInt(uiId));
+        UI.setCurrent(uI);
+
+        StreamVariable streamVariable = uI.getConnectorTracker()
+                .getStreamVariable(connectorId, variableName);
+        String secKey = uI.getConnectorTracker().getSeckey(streamVariable);
+        if (secKey.equals(parts[3])) {
+
+            ClientConnector source = session.getCommunicationManager()
+                    .getConnector(uI, connectorId);
+            String contentType = request.getContentType();
+            if (contentType.contains("boundary")) {
+                // Multipart requests contain boundary string
+                doHandleSimpleMultipartFileUpload(session, request, response,
+                        streamVariable, variableName, source,
+                        contentType.split("boundary=")[1]);
+            } else {
+                // if boundary string does not exist, the posted file is from
+                // XHR2.post(File)
+                doHandleXhrFilePost(session, request, response, streamVariable,
+                        variableName, source, request.getContentLength());
+            }
+        } else {
+            // TODO Should rethink error handling
+        }
+
+        return true;
+    }
+
+    private static String readLine(InputStream stream) throws IOException {
+        ByteArrayOutputStream bout = new ByteArrayOutputStream();
+        int readByte = stream.read();
+        while (readByte != LF) {
+            bout.write(readByte);
+            readByte = stream.read();
+        }
+        byte[] bytes = bout.toByteArray();
+        return new String(bytes, 0, bytes.length - 1, UTF8);
+    }
+
+    /**
+     * Method used to stream content from a multipart request (either from
+     * servlet or portlet request) to given StreamVariable
+     * 
+     * 
+     * @param request
+     * @param response
+     * @param streamVariable
+     * @param owner
+     * @param boundary
+     * @throws IOException
+     */
+    protected void doHandleSimpleMultipartFileUpload(VaadinSession session,
+            VaadinRequest request, VaadinResponse response,
+            StreamVariable streamVariable, String variableName,
+            ClientConnector owner, String boundary) throws IOException {
+        // multipart parsing, supports only one file for request, but that is
+        // fine for our current terminal
+
+        final InputStream inputStream = request.getInputStream();
+
+        int contentLength = request.getContentLength();
+
+        boolean atStart = false;
+        boolean firstFileFieldFound = false;
+
+        String rawfilename = "unknown";
+        String rawMimeType = "application/octet-stream";
+
+        /*
+         * Read the stream until the actual file starts (empty line). Read
+         * filename and content type from multipart headers.
+         */
+        while (!atStart) {
+            String readLine = readLine(inputStream);
+            contentLength -= (readLine.getBytes(UTF8).length + CRLF.length());
+            if (readLine.startsWith("Content-Disposition:")
+                    && readLine.indexOf("filename=") > 0) {
+                rawfilename = readLine.replaceAll(".*filename=", "");
+                char quote = rawfilename.charAt(0);
+                rawfilename = rawfilename.substring(1);
+                rawfilename = rawfilename.substring(0,
+                        rawfilename.indexOf(quote));
+                firstFileFieldFound = true;
+            } else if (firstFileFieldFound && readLine.equals("")) {
+                atStart = true;
+            } else if (readLine.startsWith("Content-Type")) {
+                rawMimeType = readLine.split(": ")[1];
+            }
+        }
+
+        contentLength -= (boundary.length() + CRLF.length() + 2
+                * DASHDASH.length() + CRLF.length());
+
+        /*
+         * Reads bytes from the underlying stream. Compares the read bytes to
+         * the boundary string and returns -1 if met.
+         * 
+         * The matching happens so that if the read byte equals to the first
+         * char of boundary string, the stream goes to "buffering mode". In
+         * buffering mode bytes are read until the character does not match the
+         * corresponding from boundary string or the full boundary string is
+         * found.
+         * 
+         * Note, if this is someday needed elsewhere, don't shoot yourself to
+         * foot and split to a top level helper class.
+         */
+        InputStream simpleMultiPartReader = new SimpleMultiPartInputStream(
+                inputStream, boundary);
+
+        /*
+         * Should report only the filename even if the browser sends the path
+         */
+        final String filename = removePath(rawfilename);
+        final String mimeType = rawMimeType;
+
+        try {
+            // TODO Shouldn't this check connectorEnabled?
+            if (owner == null) {
+                throw new UploadException(
+                        "File upload ignored because the connector for the stream variable was not found");
+            }
+            if (owner instanceof Component) {
+                if (((Component) owner).isReadOnly()) {
+                    throw new UploadException(
+                            "Warning: file upload ignored because the componente was read-only");
+                }
+            }
+            boolean forgetVariable = streamToReceiver(session,
+                    simpleMultiPartReader, streamVariable, filename, mimeType,
+                    contentLength);
+            if (forgetVariable) {
+                cleanStreamVariable(owner, variableName);
+            }
+        } catch (Exception e) {
+            session.lock();
+            try {
+                session.getCommunicationManager()
+                        .handleConnectorRelatedException(owner, e);
+            } finally {
+                session.unlock();
+            }
+        }
+        sendUploadResponse(request, response);
+
+    }
+
+    /**
+     * Used to stream plain file post (aka XHR2.post(File))
+     * 
+     * @param request
+     * @param response
+     * @param streamVariable
+     * @param owner
+     * @param contentLength
+     * @throws IOException
+     */
+    protected void doHandleXhrFilePost(VaadinSession session,
+            VaadinRequest request, VaadinResponse response,
+            StreamVariable streamVariable, String variableName,
+            ClientConnector owner, int contentLength) throws IOException {
+
+        // These are unknown in filexhr ATM, maybe add to Accept header that
+        // is accessible in portlets
+        final String filename = "unknown";
+        final String mimeType = filename;
+        final InputStream stream = request.getInputStream();
+        try {
+            /*
+             * safe cast as in GWT terminal all variable owners are expected to
+             * be components.
+             */
+            Component component = (Component) owner;
+            if (component.isReadOnly()) {
+                throw new UploadException(
+                        "Warning: file upload ignored because the component was read-only");
+            }
+            boolean forgetVariable = streamToReceiver(session, stream,
+                    streamVariable, filename, mimeType, contentLength);
+            if (forgetVariable) {
+                cleanStreamVariable(owner, variableName);
+            }
+        } catch (Exception e) {
+            session.lock();
+            try {
+                session.getCommunicationManager()
+                        .handleConnectorRelatedException(owner, e);
+            } finally {
+                session.unlock();
+            }
+        }
+        sendUploadResponse(request, response);
+    }
+
+    /**
+     * @param in
+     * @param streamVariable
+     * @param filename
+     * @param type
+     * @param contentLength
+     * @return true if the streamvariable has informed that the terminal can
+     *         forget this variable
+     * @throws UploadException
+     */
+    protected final boolean streamToReceiver(VaadinSession session,
+            final InputStream in, StreamVariable streamVariable,
+            String filename, String type, int contentLength)
+            throws UploadException {
+        if (streamVariable == null) {
+            throw new IllegalStateException(
+                    "StreamVariable for the post not found");
+        }
+
+        OutputStream out = null;
+        int totalBytes = 0;
+        StreamingStartEventImpl startedEvent = new StreamingStartEventImpl(
+                filename, type, contentLength);
+        try {
+            boolean listenProgress;
+            session.lock();
+            try {
+                streamVariable.streamingStarted(startedEvent);
+                out = streamVariable.getOutputStream();
+                listenProgress = streamVariable.listenProgress();
+            } finally {
+                session.unlock();
+            }
+
+            // Gets the output target stream
+            if (out == null) {
+                throw new NoOutputStreamException();
+            }
+
+            if (null == in) {
+                // No file, for instance non-existent filename in html upload
+                throw new NoInputStreamException();
+            }
+
+            final byte buffer[] = new byte[MAX_UPLOAD_BUFFER_SIZE];
+            int bytesReadToBuffer = 0;
+            while ((bytesReadToBuffer = in.read(buffer)) > 0) {
+                out.write(buffer, 0, bytesReadToBuffer);
+                totalBytes += bytesReadToBuffer;
+                if (listenProgress) {
+                    // update progress if listener set and contentLength
+                    // received
+                    session.lock();
+                    try {
+                        StreamingProgressEventImpl progressEvent = new StreamingProgressEventImpl(
+                                filename, type, contentLength, totalBytes);
+                        streamVariable.onProgress(progressEvent);
+                    } finally {
+                        session.unlock();
+                    }
+                }
+                if (streamVariable.isInterrupted()) {
+                    throw new UploadInterruptedException();
+                }
+            }
+
+            // upload successful
+            out.close();
+            StreamingEndEvent event = new StreamingEndEventImpl(filename, type,
+                    totalBytes);
+            session.lock();
+            try {
+                streamVariable.streamingFinished(event);
+            } finally {
+                session.unlock();
+            }
+
+        } catch (UploadInterruptedException e) {
+            // Download interrupted by application code
+            tryToCloseStream(out);
+            StreamingErrorEvent event = new StreamingErrorEventImpl(filename,
+                    type, contentLength, totalBytes, e);
+            session.lock();
+            try {
+                streamVariable.streamingFailed(event);
+            } finally {
+                session.unlock();
+            }
+            // Note, we are not throwing interrupted exception forward as it is
+            // not a terminal level error like all other exception.
+        } catch (final Exception e) {
+            tryToCloseStream(out);
+            session.lock();
+            try {
+                StreamingErrorEvent event = new StreamingErrorEventImpl(
+                        filename, type, contentLength, totalBytes, e);
+                streamVariable.streamingFailed(event);
+                // throw exception for terminal to be handled (to be passed to
+                // terminalErrorHandler)
+                throw new UploadException(e);
+            } finally {
+                session.unlock();
+            }
+        }
+        return startedEvent.isDisposed();
+    }
+
+    static void tryToCloseStream(OutputStream out) {
+        try {
+            // try to close output stream (e.g. file handle)
+            if (out != null) {
+                out.close();
+            }
+        } catch (IOException e1) {
+            // NOP
+        }
+    }
+
+    /**
+     * Removes any possible path information from the filename and returns the
+     * filename. Separators / and \\ are used.
+     * 
+     * @param name
+     * @return
+     */
+    private static String removePath(String filename) {
+        if (filename != null) {
+            filename = filename.replaceAll("^.*[/\\\\]", "");
+        }
+
+        return filename;
+    }
+
+    /**
+     * TODO document
+     * 
+     * @param request
+     * @param response
+     * @throws IOException
+     */
+    protected void sendUploadResponse(VaadinRequest request,
+            VaadinResponse response) throws IOException {
+        response.setContentType("text/html");
+        final OutputStream out = response.getOutputStream();
+        final PrintWriter outWriter = new PrintWriter(new BufferedWriter(
+                new OutputStreamWriter(out, "UTF-8")));
+        outWriter.print("<html><body>download handled</body></html>");
+        outWriter.flush();
+        out.close();
+    }
+
+    private void cleanStreamVariable(ClientConnector owner, String name) {
+        owner.getUI().getConnectorTracker()
+                .cleanStreamVariable(owner.getConnectorId(), name);
+    }
+}
diff --git a/server/src/com/vaadin/server/communication/HeartbeatHandler.java b/server/src/com/vaadin/server/communication/HeartbeatHandler.java
new file mode 100644
index 0000000000..75d4f870c1
--- /dev/null
+++ b/server/src/com/vaadin/server/communication/HeartbeatHandler.java
@@ -0,0 +1,73 @@
+/*
+ * Copyright 2000-2013 Vaadin Ltd.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.vaadin.server.communication;
+
+import java.io.IOException;
+
+import javax.servlet.http.HttpServletResponse;
+
+import com.vaadin.server.RequestHandler;
+import com.vaadin.server.VaadinRequest;
+import com.vaadin.server.VaadinResponse;
+import com.vaadin.server.VaadinSession;
+import com.vaadin.shared.ui.ui.UIConstants;
+import com.vaadin.ui.UI;
+
+/**
+ * Handles heartbeat requests. Heartbeat requests are periodically sent by the
+ * client-side to inform the server that the UI sending the heartbeat is still
+ * alive (the browser window is open, the connection is up) even when there are
+ * no UIDL requests for a prolonged period of time. UIs that do not receive
+ * either heartbeat or UIDL requests are eventually removed from the session and
+ * garbage collected.
+ * 
+ * @author Vaadin Ltd
+ * @since 7.1
+ */
+public class HeartbeatHandler implements RequestHandler {
+
+    /**
+     * Handles a heartbeat request for the given session. Reads the GET
+     * parameter named {@link UIConstants#UI_ID_PARAMETER} to identify the UI.
+     * If the UI is found in the session, sets it
+     * {@link UI#getLastHeartbeatTimestamp() heartbeat timestamp} to the current
+     * time. Otherwise, writes a HTTP Not Found error to the response.
+     */
+    @Override
+    public boolean handleRequest(VaadinSession session, VaadinRequest request,
+            VaadinResponse response) throws IOException {
+
+        UI ui = null;
+        try {
+            int uiId = Integer.parseInt(request
+                    .getParameter(UIConstants.UI_ID_PARAMETER));
+            ui = session.getUIById(uiId);
+        } catch (NumberFormatException nfe) {
+            // null-check below handles this as well
+        }
+        if (ui != null) {
+            ui.setLastHeartbeatTimestamp(System.currentTimeMillis());
+            // Ensure that the browser does not cache heartbeat responses.
+            // iOS 6 Safari requires this (#10370)
+            response.setHeader("Cache-Control", "no-cache");
+        } else {
+            response.sendError(HttpServletResponse.SC_NOT_FOUND, "UI not found");
+        }
+
+        return true;
+    }
+}
diff --git a/server/src/com/vaadin/server/communication/LegacyUidlWriter.java b/server/src/com/vaadin/server/communication/LegacyUidlWriter.java
new file mode 100644
index 0000000000..ad99a2d8b5
--- /dev/null
+++ b/server/src/com/vaadin/server/communication/LegacyUidlWriter.java
@@ -0,0 +1,118 @@
+/*
+ * Copyright 2000-2013 Vaadin Ltd.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.vaadin.server.communication;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.io.Writer;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+import java.util.logging.Logger;
+
+import com.vaadin.server.ClientConnector;
+import com.vaadin.server.LegacyPaint;
+import com.vaadin.server.PaintTarget;
+import com.vaadin.ui.Component;
+import com.vaadin.ui.LegacyComponent;
+import com.vaadin.ui.UI;
+
+/**
+ * Serializes legacy UIDL changes to JSON.
+ * 
+ * @author Vaadin Ltd
+ * @since 7.1
+ */
+public class LegacyUidlWriter implements Serializable {
+
+    /**
+     * Writes a JSON array containing the changes of all dirty
+     * {@link LegacyComponent}s in the given UI.
+     * 
+     * @param ui
+     *            The {@link UI} whose legacy changes to write
+     * @param writer
+     *            The {@link Writer} to write the JSON with
+     * @param target
+     *            The {@link PaintTarget} to use
+     * @throws IOException
+     *             If the serialization fails.
+     */
+    public void write(UI ui, Writer writer, PaintTarget target)
+            throws IOException {
+
+        Collection<ClientConnector> dirtyVisibleConnectors = ui
+                .getConnectorTracker().getDirtyVisibleConnectors();
+
+        List<Component> legacyComponents = new ArrayList<Component>();
+        for (ClientConnector connector : dirtyVisibleConnectors) {
+            // All Components that want to use paintContent must implement
+            // LegacyComponent
+            if (connector instanceof LegacyComponent) {
+                legacyComponents.add((Component) connector);
+            }
+        }
+        sortByHierarchy(legacyComponents);
+
+        writer.write("[");
+        for (Component c : legacyComponents) {
+            getLogger().fine(
+                    "Painting LegacyComponent " + c.getClass().getName() + "@"
+                            + Integer.toHexString(c.hashCode()));
+            target.startTag("change");
+            final String pid = c.getConnectorId();
+            target.addAttribute("pid", pid);
+            LegacyPaint.paint(c, target);
+            target.endTag("change");
+        }
+        writer.write("]");
+    }
+
+    private void sortByHierarchy(List<Component> paintables) {
+        // Vaadin 6 requires parents to be painted before children as component
+        // containers rely on that their updateFromUIDL method has been called
+        // before children start calling e.g. updateCaption
+        Collections.sort(paintables, new Comparator<Component>() {
+            @Override
+            public int compare(Component c1, Component c2) {
+                int depth1 = 0;
+                while (c1.getParent() != null) {
+                    depth1++;
+                    c1 = c1.getParent();
+                }
+                int depth2 = 0;
+                while (c2.getParent() != null) {
+                    depth2++;
+                    c2 = c2.getParent();
+                }
+                if (depth1 < depth2) {
+                    return -1;
+                }
+                if (depth1 > depth2) {
+                    return 1;
+                }
+                return 0;
+            }
+        });
+    }
+
+    private static final Logger getLogger() {
+        return Logger.getLogger(LegacyUidlWriter.class.getName());
+    }
+}
diff --git a/server/src/com/vaadin/server/communication/LocaleWriter.java b/server/src/com/vaadin/server/communication/LocaleWriter.java
new file mode 100644
index 0000000000..c05649da19
--- /dev/null
+++ b/server/src/com/vaadin/server/communication/LocaleWriter.java
@@ -0,0 +1,204 @@
+/*
+ * Copyright 2000-2013 Vaadin Ltd.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.vaadin.server.communication;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.io.Writer;
+import java.text.DateFormat;
+import java.text.DateFormatSymbols;
+import java.text.SimpleDateFormat;
+import java.util.Calendar;
+import java.util.GregorianCalendar;
+import java.util.List;
+import java.util.Locale;
+import java.util.logging.Logger;
+
+/**
+ * Serializes locale information to JSON.
+ * 
+ * @author Vaadin Ltd
+ * @since 7.1
+ * @deprecated See <a href="http://dev.vaadin.com/ticket/11378">ticket
+ *             #11378</a>.
+ */
+@Deprecated
+public class LocaleWriter implements Serializable {
+
+    /**
+     * Writes a JSON object containing localized strings of the given locales.
+     * 
+     * @param locales
+     *            The list of {@link Locale}s to write.
+     * @param writer
+     *            The {@link Writer} used to write the JSON.
+     * @throws IOException
+     *             If the serialization fails.
+     * 
+     */
+    public void write(List<String> locales, Writer writer) throws IOException {
+
+        // Send locale informations to client
+        writer.write("[");
+        // TODO locales are currently sent on each request; this will be fixed
+        // by implementing #11378.
+        for (int pendingLocalesIndex = 0; pendingLocalesIndex < locales.size(); pendingLocalesIndex++) {
+
+            final Locale l = generateLocale(locales.get(pendingLocalesIndex));
+            // Locale name
+            writer.write("{\"name\":\"" + l.toString() + "\",");
+
+            /*
+             * Month names (both short and full)
+             */
+            final DateFormatSymbols dfs = new DateFormatSymbols(l);
+            final String[] short_months = dfs.getShortMonths();
+            final String[] months = dfs.getMonths();
+            writer.write("\"smn\":[\""
+                    + // ShortMonthNames
+                    short_months[0] + "\",\"" + short_months[1] + "\",\""
+                    + short_months[2] + "\",\"" + short_months[3] + "\",\""
+                    + short_months[4] + "\",\"" + short_months[5] + "\",\""
+                    + short_months[6] + "\",\"" + short_months[7] + "\",\""
+                    + short_months[8] + "\",\"" + short_months[9] + "\",\""
+                    + short_months[10] + "\",\"" + short_months[11] + "\""
+                    + "],");
+            writer.write("\"mn\":[\""
+                    + // MonthNames
+                    months[0] + "\",\"" + months[1] + "\",\"" + months[2]
+                    + "\",\"" + months[3] + "\",\"" + months[4] + "\",\""
+                    + months[5] + "\",\"" + months[6] + "\",\"" + months[7]
+                    + "\",\"" + months[8] + "\",\"" + months[9] + "\",\""
+                    + months[10] + "\",\"" + months[11] + "\"" + "],");
+
+            /*
+             * Weekday names (both short and full)
+             */
+            final String[] short_days = dfs.getShortWeekdays();
+            final String[] days = dfs.getWeekdays();
+            writer.write("\"sdn\":[\""
+                    + // ShortDayNames
+                    short_days[1] + "\",\"" + short_days[2] + "\",\""
+                    + short_days[3] + "\",\"" + short_days[4] + "\",\""
+                    + short_days[5] + "\",\"" + short_days[6] + "\",\""
+                    + short_days[7] + "\"" + "],");
+            writer.write("\"dn\":[\""
+                    + // DayNames
+                    days[1] + "\",\"" + days[2] + "\",\"" + days[3] + "\",\""
+                    + days[4] + "\",\"" + days[5] + "\",\"" + days[6] + "\",\""
+                    + days[7] + "\"" + "],");
+
+            /*
+             * First day of week (0 = sunday, 1 = monday)
+             */
+            final Calendar cal = new GregorianCalendar(l);
+            writer.write("\"fdow\":" + (cal.getFirstDayOfWeek() - 1) + ",");
+
+            /*
+             * Date formatting (MM/DD/YYYY etc.)
+             */
+
+            DateFormat dateFormat = DateFormat.getDateTimeInstance(
+                    DateFormat.SHORT, DateFormat.SHORT, l);
+            if (!(dateFormat instanceof SimpleDateFormat)) {
+                getLogger().warning(
+                        "Unable to get default date pattern for locale "
+                                + l.toString());
+                dateFormat = new SimpleDateFormat();
+            }
+            final String df = ((SimpleDateFormat) dateFormat).toPattern();
+
+            int timeStart = df.indexOf("H");
+            if (timeStart < 0) {
+                timeStart = df.indexOf("h");
+            }
+            final int ampm_first = df.indexOf("a");
+            // E.g. in Korean locale AM/PM is before h:mm
+            // TODO should take that into consideration on client-side as well,
+            // now always h:mm a
+            if (ampm_first > 0 && ampm_first < timeStart) {
+                timeStart = ampm_first;
+            }
+            // Hebrew locale has time before the date
+            final boolean timeFirst = timeStart == 0;
+            String dateformat;
+            if (timeFirst) {
+                int dateStart = df.indexOf(' ');
+                if (ampm_first > dateStart) {
+                    dateStart = df.indexOf(' ', ampm_first);
+                }
+                dateformat = df.substring(dateStart + 1);
+            } else {
+                dateformat = df.substring(0, timeStart - 1);
+            }
+
+            writer.write("\"df\":\"" + dateformat.trim() + "\",");
+
+            /*
+             * Time formatting (24 or 12 hour clock and AM/PM suffixes)
+             */
+            final String timeformat = df.substring(timeStart, df.length());
+            /*
+             * Doesn't return second or milliseconds.
+             * 
+             * We use timeformat to determine 12/24-hour clock
+             */
+            final boolean twelve_hour_clock = timeformat.indexOf("a") > -1;
+            // TODO there are other possibilities as well, like 'h' in french
+            // (ignore them, too complicated)
+            final String hour_min_delimiter = timeformat.indexOf(".") > -1 ? "."
+                    : ":";
+            // outWriter.print("\"tf\":\"" + timeformat + "\",");
+            writer.write("\"thc\":" + twelve_hour_clock + ",");
+            writer.write("\"hmd\":\"" + hour_min_delimiter + "\"");
+            if (twelve_hour_clock) {
+                final String[] ampm = dfs.getAmPmStrings();
+                writer.write(",\"ampm\":[\"" + ampm[0] + "\",\"" + ampm[1]
+                        + "\"]");
+            }
+            writer.write("}");
+            if (pendingLocalesIndex < locales.size() - 1) {
+                writer.write(",");
+            }
+        }
+        writer.write("]"); // Close locales
+    }
+
+    /**
+     * Constructs a {@link Locale} instance to be sent to the client based on a
+     * short locale description string.
+     * 
+     * @see #requireLocale(String)
+     * 
+     * @param value
+     * @return
+     */
+    private Locale generateLocale(String value) {
+        final String[] temp = value.split("_");
+        if (temp.length == 1) {
+            return new Locale(temp[0]);
+        } else if (temp.length == 2) {
+            return new Locale(temp[0], temp[1]);
+        } else {
+            return new Locale(temp[0], temp[1], temp[2]);
+        }
+    }
+
+    private static final Logger getLogger() {
+        return Logger.getLogger(LocaleWriter.class.getName());
+    }
+}
diff --git a/server/src/com/vaadin/server/communication/MetadataWriter.java b/server/src/com/vaadin/server/communication/MetadataWriter.java
new file mode 100644
index 0000000000..7119e0ffeb
--- /dev/null
+++ b/server/src/com/vaadin/server/communication/MetadataWriter.java
@@ -0,0 +1,137 @@
+/*
+ * Copyright 2000-2013 Vaadin Ltd.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.vaadin.server.communication;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.io.Serializable;
+import java.io.Writer;
+import java.util.List;
+
+import com.vaadin.server.ClientConnector;
+import com.vaadin.server.ComponentSizeValidator;
+import com.vaadin.server.ComponentSizeValidator.InvalidLayout;
+import com.vaadin.server.SystemMessages;
+import com.vaadin.ui.UI;
+import com.vaadin.ui.Window;
+
+/**
+ * Serializes miscellaneous metadata to JSON.
+ * 
+ * @author Vaadin Ltd
+ * @since 7.1
+ */
+public class MetadataWriter implements Serializable {
+
+    private int timeoutInterval = -1;
+
+    /**
+     * Writes a JSON object containing metadata related to the given UI.
+     * 
+     * @param ui
+     *            The UI whose metadata to write.
+     * @param writer
+     *            The writer used.
+     * @param repaintAll
+     *            Whether the client should repaint everything.
+     * @param analyzeLayouts
+     *            Whether detected layout problems should be reported in client
+     *            and server console.
+     * @param hilightedConnector
+     *            The connector that should be highlighted on the client or null
+     *            if none.
+     * @param messages
+     *            a {@link SystemMessages} containing client-side error
+     *            messages.
+     * @throws IOException
+     *             If the serialization fails.
+     * 
+     */
+    public void write(UI ui, Writer writer, boolean repaintAll,
+            boolean analyzeLayouts, ClientConnector hilightedConnector,
+            SystemMessages messages) throws IOException {
+
+        List<InvalidLayout> invalidComponentRelativeSizes = null;
+
+        if (analyzeLayouts) {
+            invalidComponentRelativeSizes = ComponentSizeValidator
+                    .validateComponentRelativeSizes(ui.getContent(), null, null);
+
+            // Also check any existing subwindows
+            if (ui.getWindows() != null) {
+                for (Window subWindow : ui.getWindows()) {
+                    invalidComponentRelativeSizes = ComponentSizeValidator
+                            .validateComponentRelativeSizes(
+                                    subWindow.getContent(),
+                                    invalidComponentRelativeSizes, null);
+                }
+            }
+        }
+
+        writer.write("{");
+
+        boolean metaOpen = false;
+        if (repaintAll) {
+            metaOpen = true;
+            writer.write("\"repaintAll\":true");
+            if (analyzeLayouts) {
+                writer.write(", \"invalidLayouts\":");
+                writer.write("[");
+                if (invalidComponentRelativeSizes != null) {
+                    boolean first = true;
+                    for (InvalidLayout invalidLayout : invalidComponentRelativeSizes) {
+                        if (!first) {
+                            writer.write(",");
+                        } else {
+                            first = false;
+                        }
+                        invalidLayout.reportErrors(new PrintWriter(writer),
+                                System.err);
+                    }
+                }
+                writer.write("]");
+            }
+            if (hilightedConnector != null) {
+                writer.write(", \"hl\":\"");
+                writer.write(hilightedConnector.getConnectorId());
+                writer.write("\"");
+            }
+        }
+
+        // meta instruction for client to enable auto-forward to
+        // sessionExpiredURL after timer expires.
+        if (messages != null && messages.getSessionExpiredMessage() == null
+                && messages.getSessionExpiredCaption() == null
+                && messages.isSessionExpiredNotificationEnabled()) {
+            int newTimeoutInterval = ui.getSession().getSession()
+                    .getMaxInactiveInterval();
+            if (repaintAll || (timeoutInterval != newTimeoutInterval)) {
+                String escapedURL = messages.getSessionExpiredURL() == null ? ""
+                        : messages.getSessionExpiredURL().replace("/", "\\/");
+                if (metaOpen) {
+                    writer.write(",");
+                }
+                writer.write("\"timedRedirect\":{\"interval\":"
+                        + (newTimeoutInterval + 15) + ",\"url\":\""
+                        + escapedURL + "\"}");
+                metaOpen = true;
+            }
+            timeoutInterval = newTimeoutInterval;
+        }
+        writer.write("}");
+    }
+}
diff --git a/server/src/com/vaadin/server/communication/PortletListenerNotifier.java b/server/src/com/vaadin/server/communication/PortletListenerNotifier.java
new file mode 100644
index 0000000000..aff5c8a80e
--- /dev/null
+++ b/server/src/com/vaadin/server/communication/PortletListenerNotifier.java
@@ -0,0 +1,89 @@
+/*
+ * Copyright 2000-2013 Vaadin Ltd.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.vaadin.server.communication;
+
+import java.io.IOException;
+
+import javax.portlet.ActionRequest;
+import javax.portlet.ActionResponse;
+import javax.portlet.EventRequest;
+import javax.portlet.EventResponse;
+import javax.portlet.PortletRequest;
+import javax.portlet.PortletResponse;
+import javax.portlet.RenderRequest;
+import javax.portlet.RenderResponse;
+import javax.portlet.ResourceRequest;
+import javax.portlet.ResourceResponse;
+
+import com.vaadin.server.RequestHandler;
+import com.vaadin.server.ServletPortletHelper;
+import com.vaadin.server.VaadinPortletRequest;
+import com.vaadin.server.VaadinPortletResponse;
+import com.vaadin.server.VaadinPortletSession;
+import com.vaadin.server.VaadinPortletSession.PortletListener;
+import com.vaadin.server.VaadinRequest;
+import com.vaadin.server.VaadinResponse;
+import com.vaadin.server.VaadinSession;
+import com.vaadin.ui.UI;
+
+/**
+ * Notifies {@link PortletListener}s of a received portlet request.
+ * 
+ * @author Vaadin Ltd
+ * @since 7.1
+ */
+public class PortletListenerNotifier implements RequestHandler {
+
+    /**
+     * Fires portlet request events to any {@link PortletListener}s registered
+     * to the given session using
+     * {@link VaadinPortletSession#addPortletListener(PortletListener)}. The
+     * PortletListener method corresponding to the request type is invoked.
+     */
+    @Override
+    public boolean handleRequest(VaadinSession session, VaadinRequest request,
+            VaadinResponse response) throws IOException {
+
+        VaadinPortletSession sess = (VaadinPortletSession) session;
+        PortletRequest req = ((VaadinPortletRequest) request)
+                .getPortletRequest();
+        PortletResponse resp = ((VaadinPortletResponse) response)
+                .getPortletResponse();
+
+        // Finds the right UI
+        UI uI = null;
+        if (ServletPortletHelper.isUIDLRequest(request)) {
+            uI = session.getService().findUI(request);
+        }
+
+        if (request instanceof RenderRequest) {
+            sess.firePortletRenderRequest(uI, (RenderRequest) req,
+                    (RenderResponse) resp);
+        } else if (request instanceof ActionRequest) {
+            sess.firePortletActionRequest(uI, (ActionRequest) req,
+                    (ActionResponse) resp);
+        } else if (request instanceof EventRequest) {
+            sess.firePortletEventRequest(uI, (EventRequest) req,
+                    (EventResponse) resp);
+        } else if (request instanceof ResourceRequest) {
+            sess.firePortletResourceRequest(uI, (ResourceRequest) req,
+                    (ResourceResponse) resp);
+        }
+
+        return false;
+    }
+}
diff --git a/server/src/com/vaadin/server/communication/PublishedFileHandler.java b/server/src/com/vaadin/server/communication/PublishedFileHandler.java
new file mode 100644
index 0000000000..3261dc7b9f
--- /dev/null
+++ b/server/src/com/vaadin/server/communication/PublishedFileHandler.java
@@ -0,0 +1,145 @@
+/*
+ * Copyright 2000-2013 Vaadin Ltd.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.vaadin.server.communication;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.logging.Logger;
+
+import javax.servlet.http.HttpServletResponse;
+
+import com.vaadin.annotations.JavaScript;
+import com.vaadin.annotations.StyleSheet;
+import com.vaadin.server.AbstractCommunicationManager;
+import com.vaadin.server.Constants;
+import com.vaadin.server.RequestHandler;
+import com.vaadin.server.VaadinRequest;
+import com.vaadin.server.VaadinResponse;
+import com.vaadin.server.VaadinSession;
+import com.vaadin.shared.ApplicationConstants;
+
+/**
+ * Serves a connector resource from the classpath if the resource has previously
+ * been registered by calling
+ * {@link AbstractCommunicationManager#registerDependency(String, Class)}.
+ * Sending arbitrary files from the classpath is prevented by only accepting
+ * resource names that have explicitly been registered. Resources can currently
+ * only be registered by including a {@link JavaScript} or {@link StyleSheet}
+ * annotation on a Connector class.
+ * 
+ * @author Vaadin Ltd
+ * @since 7.1
+ */
+public class PublishedFileHandler implements RequestHandler {
+
+    /**
+     * Writes the connector resource identified by the request URI to the
+     * response. If a published resource corresponding to the URI path is not
+     * found, writes a HTTP Not Found error to the response.
+     */
+    @Override
+    public boolean handleRequest(VaadinSession session, VaadinRequest request,
+            VaadinResponse response) throws IOException {
+
+        String pathInfo = request.getPathInfo();
+        // + 2 to also remove beginning and ending slashes
+        String fileName = pathInfo
+                .substring(ApplicationConstants.PUBLISHED_FILE_PATH.length() + 2);
+
+        final String mimetype = response.getService().getMimeType(fileName);
+
+        // Security check: avoid accidentally serving from the UI of the
+        // classpath instead of relative to the context class
+        if (fileName.startsWith("/")) {
+            getLogger().warning(
+                    "Published file request starting with / rejected: "
+                            + fileName);
+            response.sendError(HttpServletResponse.SC_NOT_FOUND, fileName);
+            return true;
+        }
+
+        // Check that the resource name has been registered
+        // TODO PUSH refactor - is the synchronization correct at all?
+        Class<?> context;
+        synchronized (session.getCommunicationManager().getDependencies()) {
+            context = session.getCommunicationManager().getDependencies()
+                    .get(fileName);
+        }
+
+        // Security check: don't serve resource if the name hasn't been
+        // registered in the map
+        if (context == null) {
+            getLogger().warning(
+                    "Rejecting published file request for file that has not been published: "
+                            + fileName);
+            response.sendError(HttpServletResponse.SC_NOT_FOUND, fileName);
+            return true;
+        }
+
+        // Resolve file relative to the location of the context class
+        InputStream in = context.getResourceAsStream(fileName);
+        if (in == null) {
+            getLogger().warning(
+                    fileName + " published by " + context.getName()
+                            + " not found. Verify that the file "
+                            + context.getPackage().getName().replace('.', '/')
+                            + '/' + fileName
+                            + " is available on the classpath.");
+            response.sendError(HttpServletResponse.SC_NOT_FOUND, fileName);
+            return true;
+        }
+
+        // TODO Check and set cache headers
+
+        OutputStream out = null;
+        try {
+            if (mimetype != null) {
+                response.setContentType(mimetype);
+            }
+
+            out = response.getOutputStream();
+
+            final byte[] buffer = new byte[Constants.DEFAULT_BUFFER_SIZE];
+
+            int bytesRead = 0;
+            while ((bytesRead = in.read(buffer)) > 0) {
+                out.write(buffer, 0, bytesRead);
+            }
+            out.flush();
+        } finally {
+            try {
+                in.close();
+            } catch (Exception e) {
+                // Do nothing
+            }
+            if (out != null) {
+                try {
+                    out.close();
+                } catch (Exception e) {
+                    // Do nothing
+                }
+            }
+        }
+
+        return true;
+    }
+
+    private static final Logger getLogger() {
+        return Logger.getLogger(PublishedFileHandler.class.getName());
+    }
+}
diff --git a/server/src/com/vaadin/server/communication/ResourceWriter.java b/server/src/com/vaadin/server/communication/ResourceWriter.java
new file mode 100644
index 0000000000..3ba3f3f598
--- /dev/null
+++ b/server/src/com/vaadin/server/communication/ResourceWriter.java
@@ -0,0 +1,111 @@
+/*
+ * Copyright 2000-2013 Vaadin Ltd.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.vaadin.server.communication;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.Serializable;
+import java.io.Writer;
+import java.util.Iterator;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+import com.vaadin.server.AbstractCommunicationManager;
+import com.vaadin.server.JsonPaintTarget;
+import com.vaadin.ui.CustomLayout;
+import com.vaadin.ui.UI;
+
+/**
+ * Serializes resources to JSON. Currently only used for {@link CustomLayout}
+ * templates.
+ * 
+ * @author Vaadin Ltd
+ * @since 7.1
+ */
+public class ResourceWriter implements Serializable {
+
+    /**
+     * Writes a JSON object containing registered resources.
+     * 
+     * @param ui
+     *            The {@link UI} whose resources to write.
+     * @param writer
+     *            The {@link Writer} to use.
+     * @param target
+     *            The {@link JsonPaintTarget} containing the resources.
+     * @throws IOException
+     */
+    public void write(UI ui, Writer writer, JsonPaintTarget target)
+            throws IOException {
+
+        // TODO PUSH Refactor so that this is not needed
+        AbstractCommunicationManager manager = ui.getSession()
+                .getCommunicationManager();
+
+        // Precache custom layouts
+
+        // TODO We should only precache the layouts that are not
+        // cached already (plagiate from usedPaintableTypes)
+
+        writer.write("{");
+        int resourceIndex = 0;
+        for (final Iterator<Object> i = target.getUsedResources().iterator(); i
+                .hasNext();) {
+            final String resource = (String) i.next();
+            InputStream is = null;
+            try {
+                is = manager.getThemeResourceAsStream(ui, manager.getTheme(ui),
+                        resource);
+            } catch (final Exception e) {
+                // FIXME: Handle exception
+                getLogger().log(Level.FINER,
+                        "Failed to get theme resource stream.", e);
+            }
+            if (is != null) {
+
+                writer.write((resourceIndex++ > 0 ? ", " : "") + "\""
+                        + resource + "\" : ");
+                final StringBuffer layout = new StringBuffer();
+
+                try {
+                    final InputStreamReader r = new InputStreamReader(is,
+                            "UTF-8");
+                    final char[] buffer = new char[20000];
+                    int charsRead = 0;
+                    while ((charsRead = r.read(buffer)) > 0) {
+                        layout.append(buffer, 0, charsRead);
+                    }
+                    r.close();
+                } catch (final java.io.IOException e) {
+                    // FIXME: Handle exception
+                    getLogger().log(Level.INFO, "Resource transfer failed", e);
+                }
+                writer.write("\""
+                        + JsonPaintTarget.escapeJSON(layout.toString()) + "\"");
+            } else {
+                // FIXME: Handle exception
+                getLogger().severe("CustomLayout not found: " + resource);
+            }
+        }
+        writer.write("}");
+    }
+
+    private static final Logger getLogger() {
+        return Logger.getLogger(ResourceWriter.class.getName());
+    }
+}
diff --git a/server/src/com/vaadin/server/communication/ServerRpcHandler.java b/server/src/com/vaadin/server/communication/ServerRpcHandler.java
new file mode 100644
index 0000000000..8d33ea8f85
--- /dev/null
+++ b/server/src/com/vaadin/server/communication/ServerRpcHandler.java
@@ -0,0 +1,494 @@
+/*
+ * Copyright 2000-2013 Vaadin Ltd.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.vaadin.server.communication;
+
+import java.io.IOException;
+import java.io.Reader;
+import java.io.Serializable;
+import java.lang.reflect.Type;
+import java.text.CharacterIterator;
+import java.text.StringCharacterIterator;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+import org.json.JSONArray;
+import org.json.JSONException;
+
+import com.vaadin.server.AbstractCommunicationManager;
+import com.vaadin.server.AbstractCommunicationManager.InvalidUIDLSecurityKeyException;
+import com.vaadin.server.ClientConnector;
+import com.vaadin.server.JsonCodec;
+import com.vaadin.server.ServerRpcManager;
+import com.vaadin.server.ServerRpcManager.RpcInvocationException;
+import com.vaadin.server.ServerRpcMethodInvocation;
+import com.vaadin.server.VaadinRequest;
+import com.vaadin.server.VariableOwner;
+import com.vaadin.shared.ApplicationConstants;
+import com.vaadin.shared.Connector;
+import com.vaadin.shared.communication.LegacyChangeVariablesInvocation;
+import com.vaadin.shared.communication.MethodInvocation;
+import com.vaadin.shared.communication.ServerRpc;
+import com.vaadin.shared.communication.UidlValue;
+import com.vaadin.ui.Component;
+import com.vaadin.ui.ConnectorTracker;
+import com.vaadin.ui.UI;
+
+/**
+ * Handles a client-to-server message containing serialized {@link ServerRpc
+ * server RPC} invocations.
+ * 
+ * @author Vaadin Ltd
+ * @since 7.1
+ */
+public class ServerRpcHandler implements Serializable {
+
+    /* Variable records indexes */
+    public static final char VAR_BURST_SEPARATOR = '\u001d';
+
+    public static final char VAR_ESCAPE_CHARACTER = '\u001b';
+
+    private static final int MAX_BUFFER_SIZE = 64 * 1024;
+
+    // flag used in the request to indicate that the security token should be
+    // written to the response
+    private static final String WRITE_SECURITY_TOKEN_FLAG = "writeSecurityToken";
+
+    /**
+     * Reads JSON containing zero or more serialized RPC calls (including legacy
+     * variable changes) and executes the calls.
+     * 
+     * @param ui
+     *            The {@link UI} receiving the calls.
+     * @param reader
+     *            The {@link Reader} used to read the JSON.
+     * @param request
+     * @throws IOException
+     *             If reading the message fails.
+     * @throws InvalidUIDLSecurityKeyException
+     *             If the received security key does not match the one stored in
+     *             the session.
+     * @throws JSONException
+     *             If deserializing the JSON fails.
+     */
+    public void handleRpc(UI ui, Reader reader, VaadinRequest request)
+            throws IOException, InvalidUIDLSecurityKeyException, JSONException {
+
+        // Verify that there's an UI
+        if (ui == null) {
+            // This should not happen, no windows exists but
+            // session is still open.
+            getLogger().warning("Could not get UI for session");
+            return;
+        }
+
+        ui.getSession().setLastRequestTimestamp(System.currentTimeMillis());
+
+        // Change all variables based on request parameters
+        handleVariables(ui, reader, request);
+    }
+
+    private void handleVariables(UI uI, Reader reader, VaadinRequest request)
+            throws IOException, InvalidUIDLSecurityKeyException, JSONException {
+
+        String changes = getMessage(reader);
+
+        final String[] bursts = changes.split(String
+                .valueOf(VAR_BURST_SEPARATOR));
+
+        if (bursts.length > 2) {
+            throw new RuntimeException(
+                    "Multiple variable bursts not supported in Vaadin 7");
+        } else if (bursts.length <= 2) {
+            // The client sometimes sends empty messages, this is probably a bug
+            return;
+        }
+
+        // Security: double cookie submission pattern unless disabled by
+        // property
+        if (uI.getSession().getConfiguration().isXsrfProtectionEnabled()) {
+            if (bursts.length == 1 && "init".equals(bursts[0])) {
+                // init request; don't handle any variables, key sent in
+                // response.
+                // TODO This seems to be dead code
+                request.setAttribute(
+                        AbstractCommunicationManager.WRITE_SECURITY_TOKEN_FLAG,
+                        true);
+                return;
+            } else {
+                // ApplicationServlet has stored the security token in the
+                // session; check that it matched the one sent in the UIDL
+                String sessId = (String) uI
+                        .getSession()
+                        .getSession()
+                        .getAttribute(
+                                ApplicationConstants.UIDL_SECURITY_TOKEN_ID);
+
+                if (sessId == null || !sessId.equals(bursts[0])) {
+                    throw new InvalidUIDLSecurityKeyException("");
+                }
+            }
+
+        }
+        handleBurst(uI, unescapeBurst(bursts[1]));
+    }
+
+    /**
+     * Processes a message burst received from the client.
+     * 
+     * A burst can contain any number of RPC calls, including legacy variable
+     * change calls that are processed separately.
+     * 
+     * Consecutive changes to the value of the same variable are combined and
+     * changeVariables() is only called once for them. This preserves the Vaadin
+     * 6 semantics for components and add-ons that do not use Vaadin 7 RPC
+     * directly.
+     * 
+     * @param source
+     * @param uI
+     *            the UI receiving the burst
+     * @param burst
+     *            the content of the burst as a String to be parsed
+     */
+    private void handleBurst(UI uI, String burst) {
+        // TODO PUSH Refactor so that this is not needed
+        AbstractCommunicationManager manager = uI.getSession()
+                .getCommunicationManager();
+
+        try {
+            Set<Connector> enabledConnectors = new HashSet<Connector>();
+
+            List<MethodInvocation> invocations = parseInvocations(
+                    uI.getConnectorTracker(), burst);
+            for (MethodInvocation invocation : invocations) {
+                final ClientConnector connector = manager.getConnector(uI,
+                        invocation.getConnectorId());
+
+                if (connector != null && connector.isConnectorEnabled()) {
+                    enabledConnectors.add(connector);
+                }
+            }
+
+            for (int i = 0; i < invocations.size(); i++) {
+                MethodInvocation invocation = invocations.get(i);
+
+                final ClientConnector connector = manager.getConnector(uI,
+                        invocation.getConnectorId());
+                if (connector == null) {
+                    getLogger()
+                            .log(Level.WARNING,
+                                    "Received RPC call for unknown connector with id {0} (tried to invoke {1}.{2})",
+                                    new Object[] { invocation.getConnectorId(),
+                                            invocation.getInterfaceName(),
+                                            invocation.getMethodName() });
+                    continue;
+                }
+
+                if (!enabledConnectors.contains(connector)) {
+
+                    if (invocation instanceof LegacyChangeVariablesInvocation) {
+                        LegacyChangeVariablesInvocation legacyInvocation = (LegacyChangeVariablesInvocation) invocation;
+                        // TODO convert window close to a separate RPC call and
+                        // handle above - not a variable change
+
+                        // Handle special case where window-close is called
+                        // after the window has been removed from the
+                        // application or the application has closed
+                        Map<String, Object> changes = legacyInvocation
+                                .getVariableChanges();
+                        if (changes.size() == 1 && changes.containsKey("close")
+                                && Boolean.TRUE.equals(changes.get("close"))) {
+                            // Silently ignore this
+                            continue;
+                        }
+                    }
+
+                    // Connector is disabled, log a warning and move to the next
+                    String msg = "Ignoring RPC call for disabled connector "
+                            + connector.getClass().getName();
+                    if (connector instanceof Component) {
+                        String caption = ((Component) connector).getCaption();
+                        if (caption != null) {
+                            msg += ", caption=" + caption;
+                        }
+                    }
+                    getLogger().warning(msg);
+                    continue;
+                }
+
+                if (invocation instanceof ServerRpcMethodInvocation) {
+                    try {
+                        ServerRpcManager.applyInvocation(connector,
+                                (ServerRpcMethodInvocation) invocation);
+                    } catch (RpcInvocationException e) {
+                        manager.handleConnectorRelatedException(connector, e);
+                    }
+                } else {
+
+                    // All code below is for legacy variable changes
+                    LegacyChangeVariablesInvocation legacyInvocation = (LegacyChangeVariablesInvocation) invocation;
+                    Map<String, Object> changes = legacyInvocation
+                            .getVariableChanges();
+                    try {
+                        if (connector instanceof VariableOwner) {
+                            // The source parameter is never used anywhere
+                            changeVariables(null, (VariableOwner) connector,
+                                    changes);
+                        } else {
+                            throw new IllegalStateException(
+                                    "Received legacy variable change for "
+                                            + connector.getClass().getName()
+                                            + " ("
+                                            + connector.getConnectorId()
+                                            + ") which is not a VariableOwner. The client-side connector sent these legacy varaibles: "
+                                            + changes.keySet());
+                        }
+                    } catch (Exception e) {
+                        manager.handleConnectorRelatedException(connector, e);
+                    }
+                }
+            }
+        } catch (JSONException e) {
+            getLogger().warning(
+                    "Unable to parse RPC call from the client: "
+                            + e.getMessage());
+            throw new RuntimeException(e);
+        }
+    }
+
+    /**
+     * Parse a message burst from the client into a list of MethodInvocation
+     * instances.
+     * 
+     * @param connectorTracker
+     *            The ConnectorTracker used to lookup connectors
+     * @param burst
+     *            message string (JSON)
+     * @return list of MethodInvocation to perform
+     * @throws JSONException
+     */
+    private List<MethodInvocation> parseInvocations(
+            ConnectorTracker connectorTracker, String burst)
+            throws JSONException {
+        JSONArray invocationsJson = new JSONArray(burst);
+
+        ArrayList<MethodInvocation> invocations = new ArrayList<MethodInvocation>();
+
+        MethodInvocation previousInvocation = null;
+        // parse JSON to MethodInvocations
+        for (int i = 0; i < invocationsJson.length(); ++i) {
+
+            JSONArray invocationJson = invocationsJson.getJSONArray(i);
+
+            MethodInvocation invocation = parseInvocation(invocationJson,
+                    previousInvocation, connectorTracker);
+            if (invocation != null) {
+                // Can be null if the invocation was a legacy invocation and it
+                // was merged with the previous one or if the invocation was
+                // rejected because of an error.
+                invocations.add(invocation);
+                previousInvocation = invocation;
+            }
+        }
+        return invocations;
+    }
+
+    private MethodInvocation parseInvocation(JSONArray invocationJson,
+            MethodInvocation previousInvocation,
+            ConnectorTracker connectorTracker) throws JSONException {
+        String connectorId = invocationJson.getString(0);
+        String interfaceName = invocationJson.getString(1);
+        String methodName = invocationJson.getString(2);
+
+        if (connectorTracker.getConnector(connectorId) == null
+                && !connectorId
+                        .equals(ApplicationConstants.DRAG_AND_DROP_CONNECTOR_ID)) {
+            getLogger()
+                    .log(Level.WARNING,
+                            "RPC call to "
+                                    + interfaceName
+                                    + "."
+                                    + methodName
+                                    + " received for connector "
+                                    + connectorId
+                                    + " but no such connector could be found. Resynchronizing client.");
+            // This is likely an out of sync issue (client tries to update a
+            // connector which is not present). Force resync.
+            connectorTracker.markAllConnectorsDirty();
+            return null;
+        }
+
+        JSONArray parametersJson = invocationJson.getJSONArray(3);
+
+        if (LegacyChangeVariablesInvocation.isLegacyVariableChange(
+                interfaceName, methodName)) {
+            if (!(previousInvocation instanceof LegacyChangeVariablesInvocation)) {
+                previousInvocation = null;
+            }
+
+            return parseLegacyChangeVariablesInvocation(connectorId,
+                    interfaceName, methodName,
+                    (LegacyChangeVariablesInvocation) previousInvocation,
+                    parametersJson, connectorTracker);
+        } else {
+            return parseServerRpcInvocation(connectorId, interfaceName,
+                    methodName, parametersJson, connectorTracker);
+        }
+
+    }
+
+    private LegacyChangeVariablesInvocation parseLegacyChangeVariablesInvocation(
+            String connectorId, String interfaceName, String methodName,
+            LegacyChangeVariablesInvocation previousInvocation,
+            JSONArray parametersJson, ConnectorTracker connectorTracker)
+            throws JSONException {
+        if (parametersJson.length() != 2) {
+            throw new JSONException(
+                    "Invalid parameters in legacy change variables call. Expected 2, was "
+                            + parametersJson.length());
+        }
+        String variableName = parametersJson.getString(0);
+        UidlValue uidlValue = (UidlValue) JsonCodec.decodeInternalType(
+                UidlValue.class, true, parametersJson.get(1), connectorTracker);
+
+        Object value = uidlValue.getValue();
+
+        if (previousInvocation != null
+                && previousInvocation.getConnectorId().equals(connectorId)) {
+            previousInvocation.setVariableChange(variableName, value);
+            return null;
+        } else {
+            return new LegacyChangeVariablesInvocation(connectorId,
+                    variableName, value);
+        }
+    }
+
+    private ServerRpcMethodInvocation parseServerRpcInvocation(
+            String connectorId, String interfaceName, String methodName,
+            JSONArray parametersJson, ConnectorTracker connectorTracker)
+            throws JSONException {
+        ClientConnector connector = connectorTracker.getConnector(connectorId);
+
+        ServerRpcManager<?> rpcManager = connector.getRpcManager(interfaceName);
+        if (rpcManager == null) {
+            /*
+             * Security: Don't even decode the json parameters if no RpcManager
+             * corresponding to the received method invocation has been
+             * registered.
+             */
+            getLogger().warning(
+                    "Ignoring RPC call to " + interfaceName + "." + methodName
+                            + " in connector " + connector.getClass().getName()
+                            + "(" + connectorId
+                            + ") as no RPC implementation is regsitered");
+            return null;
+        }
+
+        // Use interface from RpcManager instead of loading the class based on
+        // the string name to avoid problems with OSGi
+        Class<? extends ServerRpc> rpcInterface = rpcManager.getRpcInterface();
+
+        ServerRpcMethodInvocation invocation = new ServerRpcMethodInvocation(
+                connectorId, rpcInterface, methodName, parametersJson.length());
+
+        Object[] parameters = new Object[parametersJson.length()];
+        Type[] declaredRpcMethodParameterTypes = invocation.getMethod()
+                .getGenericParameterTypes();
+
+        for (int j = 0; j < parametersJson.length(); ++j) {
+            Object parameterValue = parametersJson.get(j);
+            Type parameterType = declaredRpcMethodParameterTypes[j];
+            parameters[j] = JsonCodec.decodeInternalOrCustomType(parameterType,
+                    parameterValue, connectorTracker);
+        }
+        invocation.setParameters(parameters);
+        return invocation;
+    }
+
+    protected void changeVariables(Object source, VariableOwner owner,
+            Map<String, Object> m) {
+        owner.changeVariables(source, m);
+    }
+
+    /**
+     * Unescape encoded burst separator characters in a burst received from the
+     * client. This protects from separator injection attacks.
+     * 
+     * @param encodedValue
+     *            to decode
+     * @return decoded value
+     */
+    protected String unescapeBurst(String encodedValue) {
+        final StringBuilder result = new StringBuilder();
+        final StringCharacterIterator iterator = new StringCharacterIterator(
+                encodedValue);
+        char character = iterator.current();
+        while (character != CharacterIterator.DONE) {
+            if (VAR_ESCAPE_CHARACTER == character) {
+                character = iterator.next();
+                switch (character) {
+                case VAR_ESCAPE_CHARACTER + 0x30:
+                    // escaped escape character
+                    result.append(VAR_ESCAPE_CHARACTER);
+                    break;
+                case VAR_BURST_SEPARATOR + 0x30:
+                    // +0x30 makes these letters for easier reading
+                    result.append((char) (character - 0x30));
+                    break;
+                case CharacterIterator.DONE:
+                    // error
+                    throw new RuntimeException(
+                            "Communication error: Unexpected end of message");
+                default:
+                    // other escaped character - probably a client-server
+                    // version mismatch
+                    throw new RuntimeException(
+                            "Invalid escaped character from the client - check that the widgetset and server versions match");
+                }
+            } else {
+                // not a special character - add it to the result as is
+                result.append(character);
+            }
+            character = iterator.next();
+        }
+        return result.toString();
+    }
+
+    protected String getMessage(Reader reader) throws IOException {
+
+        StringBuilder sb = new StringBuilder(MAX_BUFFER_SIZE);
+        char[] buffer = new char[MAX_BUFFER_SIZE];
+
+        while (true) {
+            int read = reader.read(buffer);
+            if (read == -1) {
+                break;
+            }
+            sb.append(buffer, 0, read);
+        }
+
+        return sb.toString();
+    }
+
+    private static final Logger getLogger() {
+        return Logger.getLogger(ServerRpcHandler.class.getName());
+    }
+}
diff --git a/server/src/com/vaadin/server/communication/SharedStateWriter.java b/server/src/com/vaadin/server/communication/SharedStateWriter.java
new file mode 100644
index 0000000000..fdf834387f
--- /dev/null
+++ b/server/src/com/vaadin/server/communication/SharedStateWriter.java
@@ -0,0 +1,75 @@
+/*
+ * Copyright 2000-2013 Vaadin Ltd.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.vaadin.server.communication;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.io.Writer;
+import java.util.Collection;
+
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import com.vaadin.server.ClientConnector;
+import com.vaadin.server.PaintException;
+import com.vaadin.shared.communication.SharedState;
+import com.vaadin.ui.UI;
+
+/**
+ * Serializes {@link SharedState shared state} changes to JSON.
+ * 
+ * @author Vaadin Ltd
+ * @since 7.1
+ */
+public class SharedStateWriter implements Serializable {
+
+    /**
+     * Writes a JSON object containing the pending state changes of the dirty
+     * connectors of the given UI.
+     * 
+     * @param ui
+     *            The UI whose state changes should be written.
+     * @param writer
+     *            The writer to use.
+     * @throws IOException
+     *             If the serialization fails.
+     */
+    public void write(UI ui, Writer writer) throws IOException {
+
+        Collection<ClientConnector> dirtyVisibleConnectors = ui
+                .getConnectorTracker().getDirtyVisibleConnectors();
+
+        JSONObject sharedStates = new JSONObject();
+        for (ClientConnector connector : dirtyVisibleConnectors) {
+            // encode and send shared state
+            try {
+                JSONObject stateJson = connector.encodeState();
+
+                if (stateJson != null && stateJson.length() != 0) {
+                    sharedStates.put(connector.getConnectorId(), stateJson);
+                }
+            } catch (JSONException e) {
+                throw new PaintException(
+                        "Failed to serialize shared state for connector "
+                                + connector.getClass().getName() + " ("
+                                + connector.getConnectorId() + "): "
+                                + e.getMessage(), e);
+            }
+        }
+        writer.write(sharedStates.toString());
+    }
+}
diff --git a/server/src/com/vaadin/server/StreamingEndEventImpl.java b/server/src/com/vaadin/server/communication/StreamingEndEventImpl.java
index 756cadee6b..e241bbbfaf 100644
--- a/server/src/com/vaadin/server/StreamingEndEventImpl.java
+++ b/server/src/com/vaadin/server/communication/StreamingEndEventImpl.java
@@ -13,8 +13,9 @@
  * License for the specific language governing permissions and limitations under
  * the License.
  */
-package com.vaadin.server;
+package com.vaadin.server.communication;
 
+import com.vaadin.server.StreamVariable;
 import com.vaadin.server.StreamVariable.StreamingEndEvent;
 
 @SuppressWarnings("serial")
diff --git a/server/src/com/vaadin/server/StreamingErrorEventImpl.java b/server/src/com/vaadin/server/communication/StreamingErrorEventImpl.java
index 53e25399cd..1ee74c68b6 100644
--- a/server/src/com/vaadin/server/StreamingErrorEventImpl.java
+++ b/server/src/com/vaadin/server/communication/StreamingErrorEventImpl.java
@@ -13,8 +13,9 @@
  * License for the specific language governing permissions and limitations under
  * the License.
  */
-package com.vaadin.server;
+package com.vaadin.server.communication;
 
+import com.vaadin.server.StreamVariable;
 import com.vaadin.server.StreamVariable.StreamingErrorEvent;
 
 @SuppressWarnings("serial")
diff --git a/server/src/com/vaadin/server/StreamingProgressEventImpl.java b/server/src/com/vaadin/server/communication/StreamingProgressEventImpl.java
index 610cd30c13..c07e37e196 100644
--- a/server/src/com/vaadin/server/StreamingProgressEventImpl.java
+++ b/server/src/com/vaadin/server/communication/StreamingProgressEventImpl.java
@@ -13,8 +13,9 @@
  * License for the specific language governing permissions and limitations under
  * the License.
  */
-package com.vaadin.server;
+package com.vaadin.server.communication;
 
+import com.vaadin.server.StreamVariable;
 import com.vaadin.server.StreamVariable.StreamingProgressEvent;
 
 @SuppressWarnings("serial")
diff --git a/server/src/com/vaadin/server/StreamingStartEventImpl.java b/server/src/com/vaadin/server/communication/StreamingStartEventImpl.java
index 3cd41bbb6d..a7f13be499 100644
--- a/server/src/com/vaadin/server/StreamingStartEventImpl.java
+++ b/server/src/com/vaadin/server/communication/StreamingStartEventImpl.java
@@ -13,8 +13,9 @@
  * License for the specific language governing permissions and limitations under
  * the License.
  */
-package com.vaadin.server;
+package com.vaadin.server.communication;
 
+import com.vaadin.server.StreamVariable;
 import com.vaadin.server.StreamVariable.StreamingStartEvent;
 
 @SuppressWarnings("serial")
diff --git a/server/src/com/vaadin/server/communication/UIInitHandler.java b/server/src/com/vaadin/server/communication/UIInitHandler.java
new file mode 100644
index 0000000000..aea8bbd5cd
--- /dev/null
+++ b/server/src/com/vaadin/server/communication/UIInitHandler.java
@@ -0,0 +1,249 @@
+/*
+ * Copyright 2000-2013 Vaadin Ltd.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.vaadin.server.communication;
+
+import java.io.BufferedWriter;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.OutputStreamWriter;
+import java.io.PrintWriter;
+import java.io.StringWriter;
+import java.util.List;
+import java.util.Map;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import com.vaadin.annotations.PreserveOnRefresh;
+import com.vaadin.server.LegacyApplicationUIProvider;
+import com.vaadin.server.RequestHandler;
+import com.vaadin.server.UIClassSelectionEvent;
+import com.vaadin.server.UICreateEvent;
+import com.vaadin.server.UIProvider;
+import com.vaadin.server.VaadinRequest;
+import com.vaadin.server.VaadinResponse;
+import com.vaadin.server.VaadinService;
+import com.vaadin.server.VaadinSession;
+import com.vaadin.shared.ui.ui.UIConstants;
+import com.vaadin.ui.UI;
+
+/**
+ * Handles an initial request from the client to initialize a {@link UI}.
+ * 
+ * @author Vaadin Ltd
+ * @since 7.1
+ */
+public class UIInitHandler implements RequestHandler {
+
+    @Override
+    public boolean handleRequest(VaadinSession session, VaadinRequest request,
+            VaadinResponse response) throws IOException {
+
+        // NOTE! GateIn requires, for some weird reason, getOutputStream
+        // to be used instead of getWriter() (it seems to interpret
+        // application/json as a binary content type)
+        final OutputStream out = response.getOutputStream();
+        final PrintWriter outWriter = new PrintWriter(new BufferedWriter(
+                new OutputStreamWriter(out, "UTF-8")));
+
+        session.lock();
+        try {
+            assert UI.getCurrent() == null;
+
+            // Set browser information from the request
+            session.getBrowser().updateRequestDetails(request);
+
+            response.setContentType("application/json; charset=UTF-8");
+
+            UI uI = getBrowserDetailsUI(request, session);
+
+            session.getCommunicationManager().repaintAll(uI);
+
+            JSONObject params = new JSONObject();
+            params.put(UIConstants.UI_ID_PARAMETER, uI.getUIId());
+            String initialUIDL = getInitialUidl(request, uI);
+            params.put("uidl", initialUIDL);
+
+            outWriter.write(params.toString());
+            // NOTE GateIn requires the buffers to be flushed to work
+            outWriter.flush();
+            out.flush();
+        } catch (JSONException e) {
+            // TODO PUSH handle
+            e.printStackTrace();
+        } finally {
+            session.unlock();
+            outWriter.close();
+        }
+
+        return true;
+    }
+
+    private UI getBrowserDetailsUI(VaadinRequest request, VaadinSession session) {
+        VaadinService vaadinService = request.getService();
+
+        List<UIProvider> uiProviders = session.getUIProviders();
+
+        UIClassSelectionEvent classSelectionEvent = new UIClassSelectionEvent(
+                request);
+
+        UIProvider provider = null;
+        Class<? extends UI> uiClass = null;
+        for (UIProvider p : uiProviders) {
+            // Check for existing LegacyWindow
+            if (p instanceof LegacyApplicationUIProvider) {
+                LegacyApplicationUIProvider legacyProvider = (LegacyApplicationUIProvider) p;
+
+                UI existingUi = legacyProvider
+                        .getExistingUI(classSelectionEvent);
+                if (existingUi != null) {
+                    reinitUI(existingUi, request);
+                    return existingUi;
+                }
+            }
+
+            uiClass = p.getUIClass(classSelectionEvent);
+            if (uiClass != null) {
+                provider = p;
+                break;
+            }
+        }
+
+        if (provider == null || uiClass == null) {
+            return null;
+        }
+
+        // Check for an existing UI based on window.name
+
+        // Special parameter sent by vaadinBootstrap.js
+        String windowName = request.getParameter("v-wn");
+
+        Map<String, Integer> retainOnRefreshUIs = session
+                .getPreserveOnRefreshUIs();
+        if (windowName != null && !retainOnRefreshUIs.isEmpty()) {
+            // Check for a known UI
+
+            Integer retainedUIId = retainOnRefreshUIs.get(windowName);
+
+            if (retainedUIId != null) {
+                UI retainedUI = session.getUIById(retainedUIId.intValue());
+                if (uiClass.isInstance(retainedUI)) {
+                    reinitUI(retainedUI, request);
+                    return retainedUI;
+                } else {
+                    getLogger().info(
+                            "Not using retained UI in " + windowName
+                                    + " because retained UI was of type "
+                                    + retainedUI.getClass() + " but " + uiClass
+                                    + " is expected for the request.");
+                }
+            }
+        }
+
+        // No existing UI found - go on by creating and initializing one
+
+        Integer uiId = Integer.valueOf(session.getNextUIid());
+
+        // Explicit Class.cast to detect if the UIProvider does something
+        // unexpected
+        UICreateEvent event = new UICreateEvent(request, uiClass, uiId);
+        UI ui = uiClass.cast(provider.createInstance(event));
+
+        // Initialize some fields for a newly created UI
+        if (ui.getSession() != session) {
+            // Session already set for LegacyWindow
+            ui.setSession(session);
+        }
+
+        // Set thread local here so it is available in init
+        UI.setCurrent(ui);
+
+        ui.doInit(request, uiId.intValue());
+
+        session.addUI(ui);
+
+        // Remember if it should be remembered
+        if (vaadinService.preserveUIOnRefresh(provider, event)) {
+            // Remember this UI
+            if (windowName == null) {
+                getLogger().warning(
+                        "There is no window.name available for UI " + uiClass
+                                + " that should be preserved.");
+            } else {
+                session.getPreserveOnRefreshUIs().put(windowName, uiId);
+            }
+        }
+
+        return ui;
+    }
+
+    /**
+     * Updates a UI that has already been initialized but is now loaded again,
+     * e.g. because of {@link PreserveOnRefresh}.
+     * 
+     * @param ui
+     * @param request
+     */
+    private void reinitUI(UI ui, VaadinRequest request) {
+        UI.setCurrent(ui);
+
+        // Fire fragment change if the fragment has changed
+        String location = request.getParameter("v-loc");
+        if (location != null) {
+            ui.getPage().updateLocation(location);
+        }
+    }
+
+    /**
+     * Generates the initial UIDL message that can e.g. be included in a html
+     * page to avoid a separate round trip just for getting the UIDL.
+     * 
+     * @param request
+     *            the request that caused the initialization
+     * @param uI
+     *            the UI for which the UIDL should be generated
+     * @return a string with the initial UIDL message
+     * @throws JSONException
+     *             if an exception occurs while encoding output
+     * @throws IOException
+     */
+    protected String getInitialUidl(VaadinRequest request, UI uI)
+            throws JSONException, IOException {
+        StringWriter writer = new StringWriter();
+        try {
+            writer.write("{");
+            if (uI.getSession().getConfiguration().isXsrfProtectionEnabled()) {
+                writer.write(uI.getSession().getCommunicationManager()
+                        .getSecurityKeyUIDL(request));
+            }
+            new UidlWriter().write(uI, writer, true, false);
+            writer.write("}");
+
+            String initialUIDL = writer.toString();
+            getLogger().log(Level.FINE, "Initial UIDL:" + initialUIDL);
+            return initialUIDL;
+        } finally {
+            writer.close();
+        }
+    }
+
+    private static final Logger getLogger() {
+        return Logger.getLogger(UIInitHandler.class.getName());
+    }
+}
diff --git a/server/src/com/vaadin/server/communication/UidlRequestHandler.java b/server/src/com/vaadin/server/communication/UidlRequestHandler.java
new file mode 100644
index 0000000000..c200abb31d
--- /dev/null
+++ b/server/src/com/vaadin/server/communication/UidlRequestHandler.java
@@ -0,0 +1,274 @@
+/*
+ * Copyright 2000-2013 Vaadin Ltd.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.vaadin.server.communication;
+
+import java.io.BufferedWriter;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.OutputStreamWriter;
+import java.io.Writer;
+import java.util.LinkedList;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+import org.json.JSONException;
+
+import com.vaadin.server.AbstractCommunicationManager;
+import com.vaadin.server.AbstractCommunicationManager.Callback;
+import com.vaadin.server.AbstractCommunicationManager.InvalidUIDLSecurityKeyException;
+import com.vaadin.server.ClientConnector;
+import com.vaadin.server.Constants;
+import com.vaadin.server.RequestHandler;
+import com.vaadin.server.VaadinRequest;
+import com.vaadin.server.VaadinResponse;
+import com.vaadin.server.VaadinSession;
+import com.vaadin.shared.ApplicationConstants;
+import com.vaadin.shared.Version;
+import com.vaadin.ui.Component;
+import com.vaadin.ui.UI;
+
+/**
+ * Processes a UIDL request from the client.
+ * 
+ * Uses {@link ServerRpcHandler} to execute client-to-server RPC invocations and
+ * {@link UidlWriter} to write state changes and client RPC calls back to the
+ * client.
+ * 
+ * @author Vaadin Ltd
+ * @since 7.1
+ */
+public class UidlRequestHandler implements RequestHandler {
+
+    private Callback criticalNotifier;
+
+    private ServerRpcHandler rpcHandler = new ServerRpcHandler();
+
+    public UidlRequestHandler(Callback criticalNotifier) {
+        this.criticalNotifier = criticalNotifier;
+    }
+
+    @Override
+    public boolean handleRequest(VaadinSession session, VaadinRequest request,
+            VaadinResponse response) throws IOException {
+
+        UI uI = session.getService().findUI(request);
+
+        checkWidgetsetVersion(request);
+        String requestThemeName = request.getParameter("theme");
+        ClientConnector highlightedConnector;
+        // repaint requested or session has timed out and new one is created
+        boolean repaintAll;
+        final OutputStream out = response.getOutputStream();
+
+        // TODO PUSH repaintAll, analyzeLayouts, highlightConnector should be
+        // part of the message payload to make the functionality transport
+        // agnostic
+
+        repaintAll = (request
+                .getParameter(ApplicationConstants.URL_PARAMETER_REPAINT_ALL) != null);
+
+        boolean analyzeLayouts = false;
+        if (repaintAll) {
+            // analyzing can be done only with repaintAll
+            analyzeLayouts = (request
+                    .getParameter(ApplicationConstants.PARAM_ANALYZE_LAYOUTS) != null);
+
+            String pid = request
+                    .getParameter(ApplicationConstants.PARAM_HIGHLIGHT_CONNECTOR);
+            if (pid != null) {
+                highlightedConnector = uI.getConnectorTracker().getConnector(
+                        pid);
+                highlightConnector(highlightedConnector);
+            }
+        }
+
+        final Writer outWriter = new BufferedWriter(new OutputStreamWriter(out,
+                "UTF-8"));
+
+        // The rest of the process is synchronized with the session
+        // in order to guarantee that no parallel variable handling is
+        // made
+        session.lock();
+        try {
+            rpcHandler.handleRpc(uI, request.getReader(), request);
+
+            if (repaintAll) {
+                session.getCommunicationManager().repaintAll(uI);
+            }
+
+            writeUidl(request, response, uI, outWriter, repaintAll,
+                    analyzeLayouts);
+            postHandleRequest(uI);
+        } catch (JSONException e) {
+            getLogger().log(Level.SEVERE, "Error writing JSON to response", e);
+            // Refresh on client side
+            criticalNotifier.criticalNotification(request, response, null,
+                    null, null, null);
+        } catch (InvalidUIDLSecurityKeyException e) {
+            getLogger().log(Level.WARNING,
+                    "Invalid security key received from {}",
+                    request.getRemoteHost());
+            // Refresh on client side
+            criticalNotifier.criticalNotification(request, response, null,
+                    null, null, null);
+        } finally {
+            session.unlock();
+            outWriter.close();
+            requestThemeName = null;
+        }
+
+        // Ensure that the browser does not cache UIDL responses.
+        // iOS 6 Safari requires this (#9732)
+        response.setHeader("Cache-Control", "no-cache");
+
+        return true;
+    }
+
+    /**
+     * Checks that the version reported by the client (widgetset) matches that
+     * of the server.
+     * 
+     * @param request
+     */
+    private void checkWidgetsetVersion(VaadinRequest request) {
+        String widgetsetVersion = request.getParameter("v-wsver");
+        if (widgetsetVersion == null) {
+            // Only check when the widgetset version is reported. It is reported
+            // in the first UIDL request (not the initial request as it is a
+            // plain GET /)
+            return;
+        }
+
+        if (!Version.getFullVersion().equals(widgetsetVersion)) {
+            getLogger().warning(
+                    String.format(Constants.WIDGETSET_MISMATCH_INFO,
+                            Version.getFullVersion(), widgetsetVersion));
+        }
+    }
+
+    private void writeUidl(VaadinRequest request, VaadinResponse response,
+            UI ui, Writer writer, boolean repaintAll, boolean analyzeLayouts)
+            throws IOException, JSONException {
+        openJsonMessage(writer, response);
+
+        // security key
+        Object writeSecurityTokenFlag = request
+                .getAttribute(AbstractCommunicationManager.WRITE_SECURITY_TOKEN_FLAG);
+
+        if (writeSecurityTokenFlag != null) {
+            writer.write(ui.getSession().getCommunicationManager()
+                    .getSecurityKeyUIDL(request));
+        }
+
+        new UidlWriter().write(ui, writer, repaintAll, analyzeLayouts);
+
+        closeJsonMessage(writer);
+    }
+
+    /**
+     * Method called after the paint phase while still being synchronized on the
+     * session
+     * 
+     * @param uI
+     * 
+     */
+    protected void postHandleRequest(UI uI) {
+        // Remove connectors that have been detached from the session during
+        // handling of the request
+        uI.getConnectorTracker().cleanConnectorMap();
+    }
+
+    protected void closeJsonMessage(Writer outWriter) throws IOException {
+        outWriter.write("}]");
+    }
+
+    /**
+     * Writes the opening of JSON message to be sent to client.
+     * 
+     * @param outWriter
+     * @param response
+     * @throws IOException
+     */
+    protected void openJsonMessage(Writer outWriter, VaadinResponse response)
+            throws IOException {
+        // Sets the response type
+        response.setContentType("application/json; charset=UTF-8");
+        // some dirt to prevent cross site scripting
+        outWriter.write("for(;;);[{");
+    }
+
+    // TODO Does this belong here?
+    protected void highlightConnector(ClientConnector highlightedConnector) {
+        StringBuilder sb = new StringBuilder();
+        sb.append("*** Debug details of a connector:  *** \n");
+        sb.append("Type: ");
+        sb.append(highlightedConnector.getClass().getName());
+        sb.append("\nId:");
+        sb.append(highlightedConnector.getConnectorId());
+        if (highlightedConnector instanceof Component) {
+            Component component = (Component) highlightedConnector;
+            if (component.getCaption() != null) {
+                sb.append("\nCaption:");
+                sb.append(component.getCaption());
+            }
+        }
+        printHighlightedConnectorHierarchy(sb, highlightedConnector);
+        getLogger().info(sb.toString());
+    }
+
+    // TODO Does this belong here?
+    protected void printHighlightedConnectorHierarchy(StringBuilder sb,
+            ClientConnector connector) {
+        LinkedList<ClientConnector> h = new LinkedList<ClientConnector>();
+        h.add(connector);
+        ClientConnector parent = connector.getParent();
+        while (parent != null) {
+            h.addFirst(parent);
+            parent = parent.getParent();
+        }
+
+        sb.append("\nConnector hierarchy:\n");
+        VaadinSession session2 = connector.getUI().getSession();
+        sb.append(session2.getClass().getName());
+        sb.append("(");
+        sb.append(session2.getClass().getSimpleName());
+        sb.append(".java");
+        sb.append(":1)");
+        int l = 1;
+        for (ClientConnector connector2 : h) {
+            sb.append("\n");
+            for (int i = 0; i < l; i++) {
+                sb.append("  ");
+            }
+            l++;
+            Class<? extends ClientConnector> connectorClass = connector2
+                    .getClass();
+            Class<?> topClass = connectorClass;
+            while (topClass.getEnclosingClass() != null) {
+                topClass = topClass.getEnclosingClass();
+            }
+            sb.append(connectorClass.getName());
+            sb.append("(");
+            sb.append(topClass.getSimpleName());
+            sb.append(".java:1)");
+        }
+    }
+
+    private static final Logger getLogger() {
+        return Logger.getLogger(UidlRequestHandler.class.getName());
+    }
+}
diff --git a/server/src/com/vaadin/server/communication/UidlWriter.java b/server/src/com/vaadin/server/communication/UidlWriter.java
new file mode 100644
index 0000000000..0086affe91
--- /dev/null
+++ b/server/src/com/vaadin/server/communication/UidlWriter.java
@@ -0,0 +1,315 @@
+/*
+ * Copyright 2000-2013 Vaadin Ltd.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.vaadin.server.communication;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.io.Writer;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+import org.json.JSONArray;
+import org.json.JSONException;
+
+import com.vaadin.annotations.JavaScript;
+import com.vaadin.annotations.StyleSheet;
+import com.vaadin.server.AbstractCommunicationManager;
+import com.vaadin.server.AbstractCommunicationManager.ClientCache;
+import com.vaadin.server.ClientConnector;
+import com.vaadin.server.JsonPaintTarget;
+import com.vaadin.server.SystemMessages;
+import com.vaadin.server.VaadinSession;
+import com.vaadin.ui.ConnectorTracker;
+import com.vaadin.ui.UI;
+
+/**
+ * Serializes pending server-side changes to UI state to JSON. This includes
+ * shared state, client RPC invocations, connector hierarchy changes, connector
+ * type information among others.
+ * 
+ * @author Vaadin Ltd
+ * @since 7.1
+ */
+public class UidlWriter implements Serializable {
+
+    /**
+     * Writes a JSON object containing all pending changes to the given UI.
+     * 
+     * @param ui
+     *            The {@link UI} whose changes to write
+     * @param writer
+     *            The writer to use
+     * @param repaintAll
+     *            Whether the client should re-render the whole UI.
+     * @param analyzeLayouts
+     *            Whether detected layout problems should be logged.
+     * @throws IOException
+     *             If the writing fails.
+     * @throws JSONException
+     *             If the JSON serialization fails.
+     */
+    public void write(UI ui, Writer writer, boolean repaintAll,
+            boolean analyzeLayouts) throws IOException, JSONException {
+
+        ArrayList<ClientConnector> dirtyVisibleConnectors = ui
+                .getConnectorTracker().getDirtyVisibleConnectors();
+        VaadinSession session = ui.getSession();
+        AbstractCommunicationManager manager = session
+                .getCommunicationManager();
+        // Paints components
+        ConnectorTracker uiConnectorTracker = ui.getConnectorTracker();
+        getLogger().log(Level.FINE, "* Creating response to client");
+
+        getLogger().log(
+                Level.FINE,
+                "Found " + dirtyVisibleConnectors.size()
+                        + " dirty connectors to paint");
+        for (ClientConnector connector : dirtyVisibleConnectors) {
+            boolean initialized = uiConnectorTracker
+                    .isClientSideInitialized(connector);
+            connector.beforeClientResponse(!initialized);
+        }
+
+        uiConnectorTracker.setWritingResponse(true);
+        try {
+            writer.write("\"changes\" : ");
+
+            JsonPaintTarget paintTarget = new JsonPaintTarget(manager, writer,
+                    !repaintAll);
+
+            new LegacyUidlWriter().write(ui, writer, paintTarget);
+
+            paintTarget.close();
+            writer.write(", "); // close changes
+
+            // send shared state to client
+
+            // for now, send the complete state of all modified and new
+            // components
+
+            // Ideally, all this would be sent before "changes", but that causes
+            // complications with legacy components that create sub-components
+            // in their paint phase. Nevertheless, this will be processed on the
+            // client after component creation but before legacy UIDL
+            // processing.
+
+            writer.write("\"state\":");
+            new SharedStateWriter().write(ui, writer);
+            writer.write(", "); // close states
+
+            // TODO This should be optimized. The type only needs to be
+            // sent once for each connector id + on refresh. Use the same cache
+            // as
+            // widget mapping
+
+            writer.write("\"types\":");
+            new ConnectorTypeWriter().write(ui, writer, paintTarget);
+            writer.write(", "); // close states
+
+            // Send update hierarchy information to the client.
+
+            // This could be optimized aswell to send only info if hierarchy has
+            // actually changed. Much like with the shared state. Note though
+            // that an empty hierarchy is information aswell (e.g. change from 1
+            // child to 0 children)
+
+            writer.write("\"hierarchy\":");
+            new ConnectorHierarchyWriter().write(ui, writer);
+            writer.write(", "); // close hierarchy
+
+            uiConnectorTracker.markAllConnectorsClean();
+
+            // send server to client RPC calls for components in the UI, in call
+            // order
+
+            // collect RPC calls from components in the UI in the order in
+            // which they were performed, remove the calls from components
+
+            writer.write("\"rpc\" : ");
+            new ClientRpcWriter().write(ui, writer);
+            writer.write(", "); // close rpc
+
+            writer.write("\"meta\" : ");
+
+            SystemMessages messages = ui.getSession().getService()
+                    .getSystemMessages(ui.getLocale(), null);
+            // TODO hilightedConnector
+            new MetadataWriter().write(ui, writer, repaintAll, analyzeLayouts,
+                    null, messages);
+            writer.write(", ");
+
+            writer.write("\"resources\" : ");
+            new ResourceWriter().write(ui, writer, paintTarget);
+
+            Collection<Class<? extends ClientConnector>> usedClientConnectors = paintTarget
+                    .getUsedClientConnectors();
+            boolean typeMappingsOpen = false;
+            ClientCache clientCache = manager.getClientCache(ui);
+
+            List<Class<? extends ClientConnector>> newConnectorTypes = new ArrayList<Class<? extends ClientConnector>>();
+
+            for (Class<? extends ClientConnector> class1 : usedClientConnectors) {
+                if (clientCache.cache(class1)) {
+                    // client does not know the mapping key for this type, send
+                    // mapping to client
+                    newConnectorTypes.add(class1);
+
+                    if (!typeMappingsOpen) {
+                        typeMappingsOpen = true;
+                        writer.write(", \"typeMappings\" : { ");
+                    } else {
+                        writer.write(" , ");
+                    }
+                    String canonicalName = class1.getCanonicalName();
+                    writer.write("\"");
+                    writer.write(canonicalName);
+                    writer.write("\" : ");
+                    writer.write(manager.getTagForType(class1));
+                }
+            }
+            if (typeMappingsOpen) {
+                writer.write(" }");
+            }
+
+            // TODO PUSH Refactor to TypeInheritanceWriter or something
+            boolean typeInheritanceMapOpen = false;
+            if (typeMappingsOpen) {
+                // send the whole type inheritance map if any new mappings
+                for (Class<? extends ClientConnector> class1 : usedClientConnectors) {
+                    if (!ClientConnector.class.isAssignableFrom(class1
+                            .getSuperclass())) {
+                        continue;
+                    }
+                    if (!typeInheritanceMapOpen) {
+                        typeInheritanceMapOpen = true;
+                        writer.write(", \"typeInheritanceMap\" : { ");
+                    } else {
+                        writer.write(" , ");
+                    }
+                    writer.write("\"");
+                    writer.write(manager.getTagForType(class1));
+                    writer.write("\" : ");
+                    writer.write(manager
+                            .getTagForType((Class<? extends ClientConnector>) class1
+                                    .getSuperclass()));
+                }
+                if (typeInheritanceMapOpen) {
+                    writer.write(" }");
+                }
+            }
+
+            // TODO Refactor to DependencyWriter or something
+            /*
+             * Ensure super classes come before sub classes to get script
+             * dependency order right. Sub class @JavaScript might assume that
+             * 
+             * @JavaScript defined by super class is already loaded.
+             */
+            Collections.sort(newConnectorTypes, new Comparator<Class<?>>() {
+                @Override
+                public int compare(Class<?> o1, Class<?> o2) {
+                    // TODO optimize using Class.isAssignableFrom?
+                    return hierarchyDepth(o1) - hierarchyDepth(o2);
+                }
+
+                private int hierarchyDepth(Class<?> type) {
+                    if (type == Object.class) {
+                        return 0;
+                    } else {
+                        return hierarchyDepth(type.getSuperclass()) + 1;
+                    }
+                }
+            });
+
+            List<String> scriptDependencies = new ArrayList<String>();
+            List<String> styleDependencies = new ArrayList<String>();
+
+            for (Class<? extends ClientConnector> class1 : newConnectorTypes) {
+                JavaScript jsAnnotation = class1
+                        .getAnnotation(JavaScript.class);
+                if (jsAnnotation != null) {
+                    for (String uri : jsAnnotation.value()) {
+                        scriptDependencies.add(manager.registerDependency(uri,
+                                class1));
+                    }
+                }
+
+                StyleSheet styleAnnotation = class1
+                        .getAnnotation(StyleSheet.class);
+                if (styleAnnotation != null) {
+                    for (String uri : styleAnnotation.value()) {
+                        styleDependencies.add(manager.registerDependency(uri,
+                                class1));
+                    }
+                }
+            }
+
+            // Include script dependencies in output if there are any
+            if (!scriptDependencies.isEmpty()) {
+                writer.write(", \"scriptDependencies\": "
+                        + new JSONArray(scriptDependencies).toString());
+            }
+
+            // Include style dependencies in output if there are any
+            if (!styleDependencies.isEmpty()) {
+                writer.write(", \"styleDependencies\": "
+                        + new JSONArray(styleDependencies).toString());
+            }
+
+            // add any pending locale definitions requested by the client
+            writer.write(", \"locales\": ");
+            manager.printLocaleDeclarations(writer);
+
+            if (manager.getDragAndDropService() != null) {
+                manager.getDragAndDropService().printJSONResponse(writer);
+            }
+
+            for (ClientConnector connector : dirtyVisibleConnectors) {
+                uiConnectorTracker.markClientSideInitialized(connector);
+            }
+
+            assert (uiConnectorTracker.getDirtyConnectors().isEmpty()) : "Connectors have been marked as dirty during the end of the paint phase. This is most certainly not intended.";
+
+            writePerformanceData(ui, writer);
+        } catch (IOException ex) {
+            throw new RuntimeException(ex);
+        } finally {
+            uiConnectorTracker.setWritingResponse(false);
+        }
+    }
+
+    /**
+     * Adds the performance timing data (used by TestBench 3) to the UIDL
+     * response.
+     * 
+     * @throws IOException
+     */
+    private void writePerformanceData(UI ui, Writer writer) throws IOException {
+        writer.write(String.format(", \"timings\":[%d, %d]", ui.getSession()
+                .getCumulativeRequestDuration(), ui.getSession()
+                .getLastRequestDuration()));
+    }
+
+    private static final Logger getLogger() {
+        return Logger.getLogger(UidlWriter.class.getName());
+    }
+}
diff --git a/server/src/com/vaadin/ui/ConnectorTracker.java b/server/src/com/vaadin/ui/ConnectorTracker.java
index a229003224..7d741e1b28 100644
--- a/server/src/com/vaadin/ui/ConnectorTracker.java
+++ b/server/src/com/vaadin/ui/ConnectorTracker.java
@@ -17,6 +17,7 @@ package com.vaadin.ui;
 
 import java.io.IOException;
 import java.io.Serializable;
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -463,6 +464,22 @@ public class ConnectorTracker implements Serializable {
         return dirtyConnectors;
     }
 
+    /**
+     * Returns a collection of those {@link #getDirtyConnectors() dirty
+     * connectors} that are actually visible to the client.
+     * 
+     * @return A list of dirty and visible connectors.
+     */
+    public ArrayList<ClientConnector> getDirtyVisibleConnectors() {
+        ArrayList<ClientConnector> dirtyConnectors = new ArrayList<ClientConnector>();
+        for (ClientConnector c : getDirtyConnectors()) {
+            if (AbstractCommunicationManager.isConnectorVisibleToClient(c)) {
+                dirtyConnectors.add(c);
+            }
+        }
+        return dirtyConnectors;
+    }
+
     public JSONObject getDiffState(ClientConnector connector) {
         assert getConnector(connector.getConnectorId()) == connector;
         return diffStates.get(connector);
diff --git a/server/tests/src/com/vaadin/tests/server/TestSimpleMultiPartInputStream.java b/server/tests/src/com/vaadin/tests/server/TestSimpleMultiPartInputStream.java
index 84247c81c1..6907594b5e 100644
--- a/server/tests/src/com/vaadin/tests/server/TestSimpleMultiPartInputStream.java
+++ b/server/tests/src/com/vaadin/tests/server/TestSimpleMultiPartInputStream.java
@@ -7,7 +7,7 @@ import java.util.Arrays;
 
 import junit.framework.TestCase;
 
-import com.vaadin.server.AbstractCommunicationManager.SimpleMultiPartInputStream;
+import com.vaadin.server.communication.FileUploadHandler.SimpleMultiPartInputStream;
 
 public class TestSimpleMultiPartInputStream extends TestCase {
 
diff --git a/server/tests/src/com/vaadin/tests/server/TestStreamVariableMapping.java b/server/tests/src/com/vaadin/tests/server/TestStreamVariableMapping.java
index 467a76dfa6..0245ec5d5e 100644
--- a/server/tests/src/com/vaadin/tests/server/TestStreamVariableMapping.java
+++ b/server/tests/src/com/vaadin/tests/server/TestStreamVariableMapping.java
@@ -67,7 +67,7 @@ public class TestStreamVariableMapping extends TestCase {
         assertNotNull(tracker.getStreamVariable(owner.getConnectorId(),
                 variableName));
 
-        cm.cleanStreamVariable(owner, variableName);
+        tracker.cleanStreamVariable(owner.getConnectorId(), variableName);
         assertNull(tracker.getStreamVariable(owner.getConnectorId(),
                 variableName));
     }