Improve naming of fields and variables (#10242)

* Variable names to conform to naming convention.

* Use static constants where it makes sense

29 files changed, 116 insertions, 113 deletions

diff --git a/client/src/main/java/com/vaadin/client/ApplicationConnection.java b/client/src/main/java/com/vaadin/client/ApplicationConnection.java
index d9e8f545d2..3cd2590311 100644
--- a/client/src/main/java/com/vaadin/client/ApplicationConnection.java
+++ b/client/src/main/java/com/vaadin/client/ApplicationConnection.java
@@ -481,7 +481,7 @@ public class ApplicationConnection implements HasHandlers {
     }
 
     private native void initializeTestbenchHooks(
-            ComponentLocator componentLocator, String TTAppId)
+            ComponentLocator componentLocator, String ttAppId)
     /*-{
         var ap = this;
         var client = {};
@@ -527,7 +527,7 @@ public class ApplicationConnection implements HasHandlers {
         });
         client.initializing = false;
 
-        $wnd.vaadin.clients[TTAppId] = client;
+        $wnd.vaadin.clients[ttAppId] = client;
     }-*/;
 
     /**
diff --git a/client/src/main/java/com/vaadin/client/DateTimeService.java b/client/src/main/java/com/vaadin/client/DateTimeService.java
index 3c37c40b34..4883d34caf 100644
--- a/client/src/main/java/com/vaadin/client/DateTimeService.java
+++ b/client/src/main/java/com/vaadin/client/DateTimeService.java
@@ -40,6 +40,8 @@ public class DateTimeService {
     private static int[] maxDaysInMonth = { 31, 28, 31, 30, 31, 30, 31, 31, 30,
             31, 30, 31 };
 
+    private static final long MILLISECONDS_PER_DAY = 24 * 3600 * 1000;
+
     /**
      * Creates a new date time service with the application default locale.
      */
@@ -286,7 +288,6 @@ public class DateTimeService {
      * @return The ISO-8601 week number for {@literal date}
      */
     public static int getISOWeekNumber(Date date) {
-        final long MILLISECONDS_PER_DAY = 24 * 3600 * 1000;
         int dayOfWeek = date.getDay(); // 0 == sunday
 
         // ISO 8601 use weeks that start on monday so we use
diff --git a/client/src/main/java/com/vaadin/client/LayoutManager.java b/client/src/main/java/com/vaadin/client/LayoutManager.java
index 117154f9de..5a161e4bc9 100644
--- a/client/src/main/java/com/vaadin/client/LayoutManager.java
+++ b/client/src/main/java/com/vaadin/client/LayoutManager.java
@@ -43,7 +43,7 @@ public class LayoutManager {
 
     private static final String LOOP_ABORT_MESSAGE = "Aborting layout after 100 passes. This would probably be an infinite loop.";
 
-    private static final boolean debugLogging = false;
+    private static final boolean DEBUG_LOGGING = false;
 
     private ApplicationConnection connection;
     private final Set<Element> measuredNonConnectorElements = new HashSet<>();
@@ -457,7 +457,7 @@ public class LayoutManager {
                         }
                         countLayout(layoutCounts, rr);
                     }
-                    if (debugLogging) {
+                    if (DEBUG_LOGGING) {
                         updatedSet.add(layout.getConnectorId());
                     }
                 }
@@ -517,7 +517,7 @@ public class LayoutManager {
                         }
                         countLayout(layoutCounts, rr);
                     }
-                    if (debugLogging) {
+                    if (DEBUG_LOGGING) {
                         updatedSet.add(layout.getConnectorId());
                     }
                 }
@@ -525,7 +525,7 @@ public class LayoutManager {
 
             Profiler.leave("LayoutManager handle ManagedLayout");
 
-            if (debugLogging) {
+            if (DEBUG_LOGGING) {
                 JsArrayString changedCids = updatedSet.dump();
 
                 StringBuilder b = new StringBuilder("  ");
@@ -637,7 +637,7 @@ public class LayoutManager {
                     continue;
                 }
 
-                if (debugLogging) {
+                if (DEBUG_LOGGING) {
                     getLogger().info("Doing overflow fix for "
                             + Util.getConnectorString(componentConnector)
                             + " in " + Util.getConnectorString(
diff --git a/client/src/main/java/com/vaadin/client/MeasuredSize.java b/client/src/main/java/com/vaadin/client/MeasuredSize.java
index 1fcdb9d17a..bf9b64602b 100644
--- a/client/src/main/java/com/vaadin/client/MeasuredSize.java
+++ b/client/src/main/java/com/vaadin/client/MeasuredSize.java
@@ -21,7 +21,7 @@ import com.google.gwt.core.client.JsArrayString;
 import com.google.gwt.dom.client.Element;
 
 public class MeasuredSize {
-    private static final boolean debugSizeChanges = false;
+    private static final boolean DEBUG_SIZE_CHANGES = false;
 
     public static class MeasureResult {
         private final boolean widthChanged;
@@ -278,7 +278,7 @@ public class MeasuredSize {
 
     private void debugSizeChange(Element element, String sizeChangeType,
             String changedFrom, String changedTo) {
-        if (debugSizeChanges) {
+        if (DEBUG_SIZE_CHANGES) {
             getLogger().info(sizeChangeType + " has changed from " + changedFrom
                     + " to " + changedTo + " for " + element);
         }
diff --git a/client/src/main/java/com/vaadin/client/Profiler.java b/client/src/main/java/com/vaadin/client/Profiler.java
index 1b445ff2e4..e9e75a6922 100644
--- a/client/src/main/java/com/vaadin/client/Profiler.java
+++ b/client/src/main/java/com/vaadin/client/Profiler.java
@@ -47,7 +47,7 @@ public class Profiler {
 
     private static RelativeTimeSupplier RELATIVE_TIME_SUPPLIER;
 
-    private static final String evtGroup = "VaadinProfiler";
+    private static final String EVT_GROUP = "VaadinProfiler";
 
     private static ProfilerResultConsumer consumer;
 
@@ -290,7 +290,7 @@ public class Profiler {
 
         private native String getEvtGroup()
         /*-{
-            return this.evtGroup;
+            return this.EVT_GROUP;
         }-*/;
 
         private native double getMillis()
@@ -325,7 +325,7 @@ public class Profiler {
 
         public final String getEventName() {
             String group = getEvtGroup();
-            if (evtGroup.equals(group)) {
+            if (EVT_GROUP.equals(group)) {
                 return getSubSystem();
             } else {
                 return group + "." + getSubSystem();
@@ -387,7 +387,7 @@ public class Profiler {
     private static final native void logGwtEvent(String name, String type)
     /*-{
         $wnd.__gwtStatsEvent({
-            evtGroup: @com.vaadin.client.Profiler::evtGroup,
+            evtGroup: @com.vaadin.client.Profiler::EVT_GROUP,
             moduleName: @com.google.gwt.core.client.GWT::getModuleName()(),
             millis: (new Date).getTime(),
             sessionId: undefined,
@@ -463,7 +463,7 @@ public class Profiler {
         Set<Node> extendedTimeNodes = new HashSet<>();
         for (int i = 0; i < gwtStatsEvents.length(); i++) {
             GwtStatsEvent gwtStatsEvent = gwtStatsEvents.get(i);
-            if (!evtGroup.equals(gwtStatsEvent.getEvtGroup())) {
+            if (!EVT_GROUP.equals(gwtStatsEvent.getEvtGroup())) {
                 // Only log our own events to avoid problems with events which
                 // are not of type start+end
                 continue;
diff --git a/client/src/main/java/com/vaadin/client/VTooltip.java b/client/src/main/java/com/vaadin/client/VTooltip.java
index b0108dff64..399497bea1 100644
--- a/client/src/main/java/com/vaadin/client/VTooltip.java
+++ b/client/src/main/java/com/vaadin/client/VTooltip.java
@@ -56,6 +56,8 @@ public class VTooltip extends VOverlay {
     private static final int MARGIN = 4;
     public static final int TOOLTIP_EVENTS = Event.ONKEYDOWN | Event.ONMOUSEOVER
             | Event.ONMOUSEOUT | Event.ONMOUSEMOVE | Event.ONCLICK;
+    private static final int EVENT_XY_POSITION_OUTSIDE = -5000;
+
     VErrorMessage em = new VErrorMessage();
     HTML description = GWT.create(HTML.class);
 
@@ -81,6 +83,9 @@ public class VTooltip extends VOverlay {
      */
     private com.google.gwt.dom.client.Element currentElement = null;
 
+    private int tooltipEventMouseX;
+    private int tooltipEventMouseY;
+
     /**
      * Used to show tooltips; usually used via the singleton in
      * {@link ApplicationConnection}. NOTE that #setOwner(Widget)} should be
@@ -471,10 +476,6 @@ public class VTooltip extends VOverlay {
         setPopupPosition(tooltipEventMouseX, tooltipEventMouseY);
     }
 
-    private int EVENT_XY_POSITION_OUTSIDE = -5000;
-    private int tooltipEventMouseX;
-    private int tooltipEventMouseY;
-
     public void updatePosition(Event event, boolean isFocused) {
         tooltipEventMouseX = getEventX(event, isFocused);
         tooltipEventMouseY = getEventY(event, isFocused);
diff --git a/client/src/main/java/com/vaadin/client/WidgetUtil.java b/client/src/main/java/com/vaadin/client/WidgetUtil.java
index d9061321ca..3841592704 100644
--- a/client/src/main/java/com/vaadin/client/WidgetUtil.java
+++ b/client/src/main/java/com/vaadin/client/WidgetUtil.java
@@ -131,7 +131,7 @@ public class WidgetUtil {
         }
     }
 
-    private static final Element escapeHtmlHelper = DOM.createDiv();
+    private static final Element ESCAPE_HTML_HELPER = DOM.createDiv();
 
     /**
      * Converts html entities to text.
@@ -140,8 +140,8 @@ public class WidgetUtil {
      * @return escaped string presentation of given html
      */
     public static String escapeHTML(String html) {
-        DOM.setInnerText(escapeHtmlHelper, html);
-        String escapedText = DOM.getInnerHTML(escapeHtmlHelper);
+        DOM.setInnerText(ESCAPE_HTML_HELPER, html);
+        String escapedText = DOM.getInnerHTML(ESCAPE_HTML_HELPER);
         return escapedText;
     }
 
@@ -1460,7 +1460,7 @@ public class WidgetUtil {
         /*
          * Regex to parse the size.
          */
-        private static final RegExp sizePattern = RegExp
+        private static final RegExp SIZE_PATTERN = RegExp
                 .compile(SharedUtil.SIZE_PATTERN);
 
         /**
@@ -1483,7 +1483,7 @@ public class WidgetUtil {
             float size = 0;
             Unit unit = null;
 
-            MatchResult matcher = sizePattern.exec(s);
+            MatchResult matcher = SIZE_PATTERN.exec(s);
             if (matcher.getGroupCount() > 1) {
 
                 size = Float.parseFloat(matcher.getGroup(1));
@@ -1498,7 +1498,7 @@ public class WidgetUtil {
             } else {
                 throw new IllegalArgumentException(
                         "Invalid size argument: \"" + s + "\" (should match "
-                                + sizePattern.getSource() + ")");
+                                + SIZE_PATTERN.getSource() + ")");
             }
             return new CssSize(size, unit);
         }
diff --git a/client/src/main/java/com/vaadin/client/communication/JsonDecoder.java b/client/src/main/java/com/vaadin/client/communication/JsonDecoder.java
index 9a0eb60983..6e1d9c28d6 100644
--- a/client/src/main/java/com/vaadin/client/communication/JsonDecoder.java
+++ b/client/src/main/java/com/vaadin/client/communication/JsonDecoder.java
@@ -52,22 +52,22 @@ import elemental.json.JsonValue;
  */
 public class JsonDecoder {
 
-    private static final FastStringSet decodedWithoutReference = FastStringSet
+    private static final FastStringSet DECODED_WITHOUT_REFERENCE = FastStringSet
             .create();
     static {
-        decodedWithoutReference.add(String.class.getName());
-        decodedWithoutReference.add(Boolean.class.getName());
-        decodedWithoutReference.add(Byte.class.getName());
-        decodedWithoutReference.add(Character.class.getName());
-        decodedWithoutReference.add(Short.class.getName());
-        decodedWithoutReference.add(Integer.class.getName());
-        decodedWithoutReference.add(Long.class.getName());
-        decodedWithoutReference.add(Float.class.getName());
-        decodedWithoutReference.add(Double.class.getName());
-        decodedWithoutReference.add(Connector.class.getName());
-        decodedWithoutReference.add(Map.class.getName());
-        decodedWithoutReference.add(List.class.getName());
-        decodedWithoutReference.add(Set.class.getName());
+        DECODED_WITHOUT_REFERENCE.add(String.class.getName());
+        DECODED_WITHOUT_REFERENCE.add(Boolean.class.getName());
+        DECODED_WITHOUT_REFERENCE.add(Byte.class.getName());
+        DECODED_WITHOUT_REFERENCE.add(Character.class.getName());
+        DECODED_WITHOUT_REFERENCE.add(Short.class.getName());
+        DECODED_WITHOUT_REFERENCE.add(Integer.class.getName());
+        DECODED_WITHOUT_REFERENCE.add(Long.class.getName());
+        DECODED_WITHOUT_REFERENCE.add(Float.class.getName());
+        DECODED_WITHOUT_REFERENCE.add(Double.class.getName());
+        DECODED_WITHOUT_REFERENCE.add(Connector.class.getName());
+        DECODED_WITHOUT_REFERENCE.add(Map.class.getName());
+        DECODED_WITHOUT_REFERENCE.add(List.class.getName());
+        DECODED_WITHOUT_REFERENCE.add(Set.class.getName());
     }
 
     /**
@@ -193,7 +193,7 @@ public class JsonDecoder {
     }
 
     private static boolean needsReferenceValue(Type type) {
-        return !decodedWithoutReference.contains(type.getBaseTypeName());
+        return !DECODED_WITHOUT_REFERENCE.contains(type.getBaseTypeName());
     }
 
     private static Map<Object, Object> decodeMap(Type type, JsonValue jsonMap,
diff --git a/client/src/main/java/com/vaadin/client/communication/URLReference_Serializer.java b/client/src/main/java/com/vaadin/client/communication/URLReference_Serializer.java
index cc6d741183..d691bfeac5 100644
--- a/client/src/main/java/com/vaadin/client/communication/URLReference_Serializer.java
+++ b/client/src/main/java/com/vaadin/client/communication/URLReference_Serializer.java
@@ -38,10 +38,10 @@ public class URLReference_Serializer implements JSONSerializer<URLReference> {
         JsonObject json = (JsonObject) jsonValue;
         if (json.hasKey(URL_FIELD)) {
             JsonValue jsonURL = json.get(URL_FIELD);
-            String URL = (String) JsonDecoder.decodeValue(
+            String url = (String) JsonDecoder.decodeValue(
                     new Type(String.class.getName(), null), jsonURL, null,
                     connection);
-            reference.setURL(URL);
+            reference.setURL(url);
         }
         return reference;
     }
diff --git a/client/src/main/java/com/vaadin/client/componentlocator/LegacyLocatorStrategy.java b/client/src/main/java/com/vaadin/client/componentlocator/LegacyLocatorStrategy.java
index d2c818f2f5..e775793e6f 100644
--- a/client/src/main/java/com/vaadin/client/componentlocator/LegacyLocatorStrategy.java
+++ b/client/src/main/java/com/vaadin/client/componentlocator/LegacyLocatorStrategy.java
@@ -74,7 +74,7 @@ public class LegacyLocatorStrategy implements LocatorStrategy {
 
     private final ApplicationConnection client;
 
-    private static final RegExp validSyntax = RegExp.compile(
+    private static final RegExp VALID_SYNTAX = RegExp.compile(
             "^((\\w+::)?((PID_S)?\\w[-$_a-zA-Z0-9.' ]*)?)?(/[-$_a-zA-Z0-9]+\\[\\d+\\])*/?(#.*)?$");
 
     public LegacyLocatorStrategy(ApplicationConnection clientConnection) {
@@ -83,7 +83,7 @@ public class LegacyLocatorStrategy implements LocatorStrategy {
 
     @Override
     public boolean validatePath(String path) {
-        return validSyntax.test(path);
+        return VALID_SYNTAX.test(path);
     }
 
     @Override
diff --git a/client/src/main/java/com/vaadin/client/debug/internal/VDebugWindow.java b/client/src/main/java/com/vaadin/client/debug/internal/VDebugWindow.java
index 7ac67d349a..bfb4ca04ff 100644
--- a/client/src/main/java/com/vaadin/client/debug/internal/VDebugWindow.java
+++ b/client/src/main/java/com/vaadin/client/debug/internal/VDebugWindow.java
@@ -111,8 +111,8 @@ public final class VDebugWindow extends VOverlay {
     protected int fontSize = 1; // 0-2
 
     // Timers since application start, and last timer reset
-    private static final Duration start = new Duration();
-    private static Duration lastReset = start;
+    private static final Duration START = new Duration();
+    private static Duration lastReset = START;
 
     // outer panel
     protected FlowPanel window = new FlowPanel();
@@ -637,7 +637,7 @@ public final class VDebugWindow extends VOverlay {
      * @return
      */
     static int getMillisSinceStart() {
-        return start.elapsedMillis();
+        return START.elapsedMillis();
     }
 
     /**
diff --git a/client/src/main/java/com/vaadin/client/event/PointerEventSupport.java b/client/src/main/java/com/vaadin/client/event/PointerEventSupport.java
index 1a9fefd703..9386e4612e 100644
--- a/client/src/main/java/com/vaadin/client/event/PointerEventSupport.java
+++ b/client/src/main/java/com/vaadin/client/event/PointerEventSupport.java
@@ -27,14 +27,14 @@ import com.vaadin.client.event.PointerEvent.EventType;
  */
 public class PointerEventSupport {
 
-    private static final PointerEventSupportImpl impl = GWT
+    private static final PointerEventSupportImpl IMPL = GWT
             .create(PointerEventSupportImpl.class);
 
     private PointerEventSupport() {
     }
 
     public static void init() {
-        impl.init();
+        IMPL.init();
     }
 
     /**
@@ -42,7 +42,7 @@ public class PointerEventSupport {
      *         otherwise
      */
     public static boolean isSupported() {
-        return impl.isSupported();
+        return IMPL.isSupported();
     }
 
     /**
@@ -50,6 +50,6 @@ public class PointerEventSupport {
      * @return the native event name of the given event
      */
     public static String getNativeEventName(EventType eventType) {
-        return impl.getNativeEventName(eventType);
+        return IMPL.getNativeEventName(eventType);
     }
 }
diff --git a/client/src/main/java/com/vaadin/client/extensions/javascriptmanager/JavaScriptManagerConnector.java b/client/src/main/java/com/vaadin/client/extensions/javascriptmanager/JavaScriptManagerConnector.java
index 1fc86201bd..4381caddd0 100644
--- a/client/src/main/java/com/vaadin/client/extensions/javascriptmanager/JavaScriptManagerConnector.java
+++ b/client/src/main/java/com/vaadin/client/extensions/javascriptmanager/JavaScriptManagerConnector.java
@@ -40,8 +40,8 @@ public class JavaScriptManagerConnector extends AbstractExtensionConnector {
     protected void init() {
         registerRpc(ExecuteJavaScriptRpc.class, new ExecuteJavaScriptRpc() {
             @Override
-            public void executeJavaScript(String Script) {
-                eval(Script);
+            public void executeJavaScript(String script) {
+                eval(script);
             }
         });
     }
diff --git a/client/src/main/java/com/vaadin/client/ui/TouchScrollDelegate.java b/client/src/main/java/com/vaadin/client/ui/TouchScrollDelegate.java
index af8f918a4a..185b93c8a8 100644
--- a/client/src/main/java/com/vaadin/client/ui/TouchScrollDelegate.java
+++ b/client/src/main/java/com/vaadin/client/ui/TouchScrollDelegate.java
@@ -101,7 +101,7 @@ public class TouchScrollDelegate implements NativePreviewHandler {
 
     private static TouchScrollDelegate activeScrollDelegate;
 
-    private static final boolean androidWithBrokenScrollTop = BrowserInfo.get()
+    private static final boolean ANDROID_WITH_BROKEN_SCROLL_TOP = BrowserInfo.get()
             .isAndroidWithBrokenScrollTop();
 
     /**
@@ -330,7 +330,7 @@ public class TouchScrollDelegate implements NativePreviewHandler {
     }
 
     private int getScrollTop() {
-        if (androidWithBrokenScrollTop) {
+        if (ANDROID_WITH_BROKEN_SCROLL_TOP) {
             if (scrolledElement.getPropertyJSO("_vScrollTop") != null) {
                 return scrolledElement.getPropertyInt("_vScrollTop");
             }
@@ -360,7 +360,7 @@ public class TouchScrollDelegate implements NativePreviewHandler {
         VConsole.log("Animate " + time + " " + from + " " + to);
         int translateTo = -to + origScrollTop;
         int fromY = -from + origScrollTop;
-        if (androidWithBrokenScrollTop) {
+        if (ANDROID_WITH_BROKEN_SCROLL_TOP) {
             fromY -= origScrollTop;
             translateTo -= origScrollTop;
         }
@@ -380,7 +380,7 @@ public class TouchScrollDelegate implements NativePreviewHandler {
      * scrolltop, causing onscroll event.
      */
     private void moveTransformationToScrolloffset() {
-        if (androidWithBrokenScrollTop) {
+        if (ANDROID_WITH_BROKEN_SCROLL_TOP) {
             scrolledElement.setPropertyInt("_vScrollTop", finalScrollTop);
             if (scrollHandler != null) {
                 scrollHandler.onScroll(null);
@@ -465,7 +465,7 @@ public class TouchScrollDelegate implements NativePreviewHandler {
 
     private void quickSetScrollPosition(int deltaX, int deltaY) {
         deltaScrollPos = deltaY;
-        if (androidWithBrokenScrollTop) {
+        if (ANDROID_WITH_BROKEN_SCROLL_TOP) {
             deltaY += origScrollTop;
             translateTo(-deltaY);
         } else {
@@ -570,7 +570,7 @@ public class TouchScrollDelegate implements NativePreviewHandler {
 
         int translateTo = -finalY + origScrollTop;
         int fromY = -currentY + origScrollTop;
-        if (androidWithBrokenScrollTop) {
+        if (ANDROID_WITH_BROKEN_SCROLL_TOP) {
             fromY -= origScrollTop;
             translateTo -= origScrollTop;
         }
@@ -652,7 +652,7 @@ public class TouchScrollDelegate implements NativePreviewHandler {
     }
 
     private int getMaxOverScroll() {
-        return androidWithBrokenScrollTop ? 0
+        return ANDROID_WITH_BROKEN_SCROLL_TOP ? 0
                 : scrolledElement.getClientHeight() / 3;
     }
 
diff --git a/client/src/main/java/com/vaadin/client/ui/VAbstractPopupCalendar.java b/client/src/main/java/com/vaadin/client/ui/VAbstractPopupCalendar.java
index 18d8dbdfee..70ada4d70e 100644
--- a/client/src/main/java/com/vaadin/client/ui/VAbstractPopupCalendar.java
+++ b/client/src/main/java/com/vaadin/client/ui/VAbstractPopupCalendar.java
@@ -98,7 +98,7 @@ public abstract class VAbstractPopupCalendar<PANEL extends VAbstractCalendarPane
 
     private Element descriptionForAssistiveDevicesElement;
 
-    private final String CALENDAR_TOGGLE_ID = "popupButton";
+    private static final String CALENDAR_TOGGLE_ID = "popupButton";
 
     public VAbstractPopupCalendar(PANEL calendarPanel, R resolution) {
         super(resolution);
diff --git a/client/src/main/java/com/vaadin/client/ui/VAudio.java b/client/src/main/java/com/vaadin/client/ui/VAudio.java
index cf80c80e37..31e3165066 100644
--- a/client/src/main/java/com/vaadin/client/ui/VAudio.java
+++ b/client/src/main/java/com/vaadin/client/ui/VAudio.java
@@ -20,7 +20,7 @@ import com.google.gwt.dom.client.AudioElement;
 import com.google.gwt.dom.client.Document;
 
 public class VAudio extends VMediaBase {
-    private static String CLASSNAME = "v-audio";
+    private static final String CLASSNAME = "v-audio";
 
     private AudioElement audio;
 
diff --git a/client/src/main/java/com/vaadin/client/ui/VMenuBar.java b/client/src/main/java/com/vaadin/client/ui/VMenuBar.java
index 607128c43c..5ee7cb0860 100644
--- a/client/src/main/java/com/vaadin/client/ui/VMenuBar.java
+++ b/client/src/main/java/com/vaadin/client/ui/VMenuBar.java
@@ -505,7 +505,7 @@ public class VMenuBar extends SimpleFocusablePanel
      * root menus on mouse hover.
      */
     private static class LazyCloser extends Timer {
-        static LazyCloser INSTANCE;
+        static LazyCloser instance;
         private VMenuBar activeRoot;
 
         @Override
@@ -517,27 +517,27 @@ public class VMenuBar extends SimpleFocusablePanel
         }
 
         public static void cancelClosing() {
-            if (INSTANCE != null) {
-                INSTANCE.cancel();
+            if (instance != null) {
+                instance.cancel();
             }
         }
 
         public static void prepare(VMenuBar vMenuBar) {
-            if (INSTANCE == null) {
-                INSTANCE = new LazyCloser();
+            if (instance == null) {
+                instance = new LazyCloser();
             }
-            if (INSTANCE.activeRoot == vMenuBar) {
-                INSTANCE.cancel();
-            } else if (INSTANCE.activeRoot != null) {
-                INSTANCE.cancel();
-                INSTANCE.run();
+            if (instance.activeRoot == vMenuBar) {
+                instance.cancel();
+            } else if (instance.activeRoot != null) {
+                instance.cancel();
+                instance.run();
             }
-            INSTANCE.activeRoot = vMenuBar;
+            instance.activeRoot = vMenuBar;
         }
 
         public static void schedule() {
-            if (INSTANCE != null && INSTANCE.activeRoot != null) {
-                INSTANCE.schedule(750);
+            if (instance != null && instance.activeRoot != null) {
+                instance.schedule(750);
             }
         }
 
@@ -1587,7 +1587,7 @@ public class VMenuBar extends SimpleFocusablePanel
 
     }
 
-    private final String SUBPART_PREFIX = "item";
+    private static final String SUBPART_PREFIX = "item";
 
     @Override
     public com.google.gwt.user.client.Element getSubPartElement(
diff --git a/client/src/main/java/com/vaadin/client/ui/VNotification.java b/client/src/main/java/com/vaadin/client/ui/VNotification.java
index 7cc47d90f1..37255ff4bb 100644
--- a/client/src/main/java/com/vaadin/client/ui/VNotification.java
+++ b/client/src/main/java/com/vaadin/client/ui/VNotification.java
@@ -75,11 +75,11 @@ public class VNotification extends VOverlay {
     public static final int DELAY_NONE = 0;
 
     private static final String STYLENAME = "v-Notification";
-    private static final int mouseMoveThreshold = 7;
+    private static final int MOUSE_MOVE_THRESHOLD = 7;
     private static final int Z_INDEX_BASE = 20000;
     public static final String STYLE_SYSTEM = "system";
 
-    private static final List<VNotification> notifications = new ArrayList<>();
+    private static final List<VNotification> NOTIFICATIONS = new ArrayList<>();
 
     private boolean infiniteDelay = false;
     private int hideDelay = 0;
@@ -254,7 +254,7 @@ public class VNotification extends VOverlay {
         setPosition(position);
         super.show();
         updatePositionOffsets(position);
-        notifications.add(this);
+        NOTIFICATIONS.add(this);
         positionOrSizeUpdated();
         /**
          * Android 4 fails to render notifications correctly without a little
@@ -288,7 +288,7 @@ public class VNotification extends VOverlay {
             delay.cancel();
         }
         // Run only once
-        if (notifications.contains(this)) {
+        if (NOTIFICATIONS.contains(this)) {
             DOM.removeEventPreview(this);
 
             // Still animating in, wait for it to finish before touching
@@ -310,7 +310,7 @@ public class VNotification extends VOverlay {
             } else {
                 VNotification.super.hide();
                 fireEvent(new HideEvent(this));
-                notifications.remove(this);
+                NOTIFICATIONS.remove(this);
             }
         }
     }
@@ -433,9 +433,9 @@ public class VNotification extends VOverlay {
                 x = DOM.eventGetClientX(event);
                 y = DOM.eventGetClientY(event);
             } else if (Math
-                    .abs(DOM.eventGetClientX(event) - x) > mouseMoveThreshold
+                    .abs(DOM.eventGetClientX(event) - x) > MOUSE_MOVE_THRESHOLD
                     || Math.abs(DOM.eventGetClientY(event)
-                            - y) > mouseMoveThreshold) {
+                            - y) > MOUSE_MOVE_THRESHOLD) {
                 hideAfterDelay();
             }
             break;
@@ -592,7 +592,7 @@ public class VNotification extends VOverlay {
      * TODO Should this be a generic Overlay feature instead?
      */
     public static void bringNotificationsToFront() {
-        for (VNotification notification : notifications) {
+        for (VNotification notification : NOTIFICATIONS) {
             DOM.removeEventPreview(notification);
             DOM.addEventPreview(notification);
         }
diff --git a/client/src/main/java/com/vaadin/client/ui/VSlider.java b/client/src/main/java/com/vaadin/client/ui/VSlider.java
index 22c681d5c2..ec4167f9fa 100644
--- a/client/src/main/java/com/vaadin/client/ui/VSlider.java
+++ b/client/src/main/java/com/vaadin/client/ui/VSlider.java
@@ -75,7 +75,7 @@ public class VSlider extends SimpleFocusablePanel
 
     /* DOM element for slider's base */
     private final Element base;
-    private final int BASE_BORDER_WIDTH = 1;
+    private static final int BASE_BORDER_WIDTH = 1;
 
     /* DOM element for slider's handle */
     private final Element handle;
diff --git a/client/src/main/java/com/vaadin/client/ui/VTabsheet.java b/client/src/main/java/com/vaadin/client/ui/VTabsheet.java
index c2cbd626e8..e7da389113 100644
--- a/client/src/main/java/com/vaadin/client/ui/VTabsheet.java
+++ b/client/src/main/java/com/vaadin/client/ui/VTabsheet.java
@@ -185,7 +185,7 @@ public class VTabsheet extends VTabsheetBase
 
             setStyleName(td, TD_DISABLED_CLASSNAME, !enabled);
             if (!enabled) {
-                focusImpl.setTabIndex(td, -1);
+                FOCUS_IMPL.setTabIndex(td, -1);
             }
         }
 
@@ -297,11 +297,11 @@ public class VTabsheet extends VTabsheetBase
 
         public void focus() {
             getTabsheet().scrollIntoView(this);
-            focusImpl.focus(td);
+            FOCUS_IMPL.focus(td);
         }
 
         public void blur() {
-            focusImpl.blur(td);
+            FOCUS_IMPL.blur(td);
         }
 
         public boolean hasTooltip() {
@@ -739,6 +739,9 @@ public class VTabsheet extends VTabsheetBase
     public static final String TABS_CLASSNAME = CLASSNAME + "-tabcontainer";
     public static final String SCROLLER_CLASSNAME = CLASSNAME + "-scroller";
 
+    private static final FocusImpl FOCUS_IMPL = FocusImpl
+            .getFocusImplForPanel();
+
     /** For internal use only. May be removed or replaced in the future. */
     // tabbar and 'scroller' container
     public final Element tabs;
@@ -749,8 +752,6 @@ public class VTabsheet extends VTabsheetBase
      */
     int tabulatorIndex = 0;
 
-    private static final FocusImpl focusImpl = FocusImpl.getFocusImplForPanel();
-
     // tab-scroller element
     private final Element scroller;
     // tab-scroller next button element
diff --git a/client/src/main/java/com/vaadin/client/ui/VUI.java b/client/src/main/java/com/vaadin/client/ui/VUI.java
index 6e3ffd716f..6ee44aa930 100644
--- a/client/src/main/java/com/vaadin/client/ui/VUI.java
+++ b/client/src/main/java/com/vaadin/client/ui/VUI.java
@@ -50,7 +50,7 @@ public class VUI extends SimplePanel implements ResizeHandler,
         com.google.gwt.user.client.ui.Focusable, HasResizeHandlers,
         HasScrollHandlers {
 
-    private static int MONITOR_PARENT_TIMER_INTERVAL = 1000;
+    private static final int MONITOR_PARENT_TIMER_INTERVAL = 1000;
 
     /** For internal use only. May be removed or replaced in the future. */
     public String id;
diff --git a/client/src/main/java/com/vaadin/client/ui/VWindow.java b/client/src/main/java/com/vaadin/client/ui/VWindow.java
index 8ac90386c7..b27c803b75 100644
--- a/client/src/main/java/com/vaadin/client/ui/VWindow.java
+++ b/client/src/main/java/com/vaadin/client/ui/VWindow.java
@@ -81,7 +81,7 @@ public class VWindow extends VOverlay implements ShortcutActionHandlerOwner,
 
     private static List<VWindow> windowOrder = new ArrayList<>();
 
-    private static HandlerManager WINDOW_ORDER_HANDLER = new HandlerManager(
+    private static final HandlerManager WINDOW_ORDER_HANDLER = new HandlerManager(
             VWindow.class);
 
     private static boolean orderingDefered;
diff --git a/client/src/main/java/com/vaadin/client/ui/formlayout/FormLayoutConnector.java b/client/src/main/java/com/vaadin/client/ui/formlayout/FormLayoutConnector.java
index ea9fd57c26..857d4e07b3 100644
--- a/client/src/main/java/com/vaadin/client/ui/formlayout/FormLayoutConnector.java
+++ b/client/src/main/java/com/vaadin/client/ui/formlayout/FormLayoutConnector.java
@@ -70,7 +70,7 @@ public class FormLayoutConnector extends AbstractLayoutConnector
 
     private Map<ComponentConnector, String> oldMaxWidths = null;
 
-    private static final ElementResizeListener dummyFirstCellResizeListener = new ElementResizeListener() {
+    private static final ElementResizeListener DUMMY_FIRST_CELL_RESIZE_LISTENER = new ElementResizeListener() {
         @Override
         public void onElementResize(ElementResizeEvent e) {
             // Ignore event, listener added just to make measurements available
@@ -220,7 +220,7 @@ public class FormLayoutConnector extends AbstractLayoutConnector
         Element td = findFirstComponentTd();
         if (td != null) {
             getLayoutManager().addElementResizeListener(td,
-                    dummyFirstCellResizeListener);
+                    DUMMY_FIRST_CELL_RESIZE_LISTENER);
         }
     }
 
@@ -228,7 +228,7 @@ public class FormLayoutConnector extends AbstractLayoutConnector
         Element td = findFirstComponentTd();
         if (td != null) {
             getLayoutManager().removeElementResizeListener(td,
-                    dummyFirstCellResizeListener);
+                    DUMMY_FIRST_CELL_RESIZE_LISTENER);
         }
     }
 
diff --git a/client/src/main/java/com/vaadin/client/ui/popupview/VisibilityChangeEvent.java b/client/src/main/java/com/vaadin/client/ui/popupview/VisibilityChangeEvent.java
index 06380eef28..02eee0804e 100644
--- a/client/src/main/java/com/vaadin/client/ui/popupview/VisibilityChangeEvent.java
+++ b/client/src/main/java/com/vaadin/client/ui/popupview/VisibilityChangeEvent.java
@@ -19,7 +19,7 @@ import com.google.gwt.event.shared.GwtEvent;
 
 public class VisibilityChangeEvent extends GwtEvent<VisibilityChangeHandler> {
 
-    private static Type<VisibilityChangeHandler> TYPE;
+    private static Type<VisibilityChangeHandler> type;
 
     private boolean visible;
 
@@ -37,10 +37,10 @@ public class VisibilityChangeEvent extends GwtEvent<VisibilityChangeHandler> {
     }
 
     public static Type<VisibilityChangeHandler> getType() {
-        if (TYPE == null) {
-            TYPE = new Type<>();
+        if (type == null) {
+            type = new Type<>();
         }
-        return TYPE;
+        return type;
     }
 
     @Override
diff --git a/client/src/main/java/com/vaadin/client/ui/richtextarea/VRichTextToolbar.java b/client/src/main/java/com/vaadin/client/ui/richtextarea/VRichTextToolbar.java
index d235ddeca3..f3ebb34d7f 100644
--- a/client/src/main/java/com/vaadin/client/ui/richtextarea/VRichTextToolbar.java
+++ b/client/src/main/java/com/vaadin/client/ui/richtextarea/VRichTextToolbar.java
@@ -201,7 +201,7 @@ public class VRichTextToolbar extends Composite {
                 fonts.setSelectedIndex(0);
             } else if (sender == fontSizes) {
                 basic.setFontSize(
-                        fontSizesConstants[fontSizes.getSelectedIndex() - 1]);
+                        FONT_SIZES_CONSTANTS[fontSizes.getSelectedIndex() - 1]);
                 fontSizes.setSelectedIndex(0);
             }
         }
@@ -275,7 +275,7 @@ public class VRichTextToolbar extends Composite {
         }
     }
 
-    private static final RichTextArea.FontSize[] fontSizesConstants = {
+    private static final RichTextArea.FontSize[] FONT_SIZES_CONSTANTS = {
             RichTextArea.FontSize.XX_SMALL, RichTextArea.FontSize.X_SMALL,
             RichTextArea.FontSize.SMALL, RichTextArea.FontSize.MEDIUM,
             RichTextArea.FontSize.LARGE, RichTextArea.FontSize.X_LARGE,
diff --git a/client/src/main/java/com/vaadin/client/widget/escalator/ScrollbarBundle.java b/client/src/main/java/com/vaadin/client/widget/escalator/ScrollbarBundle.java
index bb1686ae83..c979325f7e 100644
--- a/client/src/main/java/com/vaadin/client/widget/escalator/ScrollbarBundle.java
+++ b/client/src/main/java/com/vaadin/client/widget/escalator/ScrollbarBundle.java
@@ -50,7 +50,7 @@ import com.vaadin.client.widget.grid.events.ScrollHandler;
  */
 public abstract class ScrollbarBundle implements DeferredWorker {
 
-    private static final boolean supportsRequestAnimationFrame = new AnimationSupportDetector()
+    private static final boolean SUPPORTS_REQUEST_ANIMATION_FRAME = new AnimationSupportDetector()
             .isNativelySupported();
 
     private class ScrollEventFirer {
@@ -92,7 +92,7 @@ public abstract class ScrollbarBundle implements DeferredWorker {
                  * We'll gather all the scroll events, and only fire once, once
                  * everything has calmed down.
                  */
-                if (supportsRequestAnimationFrame) {
+                if (SUPPORTS_REQUEST_ANIMATION_FRAME) {
                     // Chrome MUST use this as deferred commands will sometimes
                     // be run with a 300+ ms delay when scrolling.
                     AnimationScheduler.get().requestAnimationFrame(
diff --git a/client/src/main/java/com/vaadin/client/widget/grid/datasources/ListSorter.java b/client/src/main/java/com/vaadin/client/widget/grid/datasources/ListSorter.java
index 07fc05622b..d5f3e24528 100644
--- a/client/src/main/java/com/vaadin/client/widget/grid/datasources/ListSorter.java
+++ b/client/src/main/java/com/vaadin/client/widget/grid/datasources/ListSorter.java
@@ -144,17 +144,17 @@ public class ListSorter<T> {
                     Grid.Column column = o.getColumn();
                     Comparator cmp = ListSorter.this.comparators.get(column);
                     int result = 0;
-                    Object value_a = column.getValue(a);
-                    Object value_b = column.getValue(b);
+                    Object valueA = column.getValue(a);
+                    Object valueB = column.getValue(b);
                     if (cmp != null) {
-                        result = cmp.compare(value_a, value_b);
+                        result = cmp.compare(valueA, valueB);
                     } else {
-                        if (!(value_a instanceof Comparable)) {
+                        if (!(valueA instanceof Comparable)) {
                             throw new IllegalStateException("Column " + column
                                     + " has no assigned comparator and value "
-                                    + value_a + " isn't naturally comparable");
+                                    + valueA + " isn't naturally comparable");
                         }
-                        result = ((Comparable) value_a).compareTo(value_b);
+                        result = ((Comparable) valueA).compareTo(valueB);
                     }
 
                     if (result != 0) {
diff --git a/client/src/main/java/com/vaadin/client/widget/grid/selection/SelectionEvent.java b/client/src/main/java/com/vaadin/client/widget/grid/selection/SelectionEvent.java
index 4145919f2f..fd65e63cea 100644
--- a/client/src/main/java/com/vaadin/client/widget/grid/selection/SelectionEvent.java
+++ b/client/src/main/java/com/vaadin/client/widget/grid/selection/SelectionEvent.java
@@ -32,7 +32,7 @@ import com.vaadin.client.widgets.Grid;
 @SuppressWarnings("rawtypes")
 public class SelectionEvent<T> extends GwtEvent<SelectionHandler> {
 
-    private static final Type<SelectionHandler> eventType = new Type<>();
+    private static final Type<SelectionHandler> EVENT_TYPE = new Type<>();
 
     private final Grid<T> grid;
     private final List<T> added;
@@ -142,12 +142,12 @@ public class SelectionEvent<T> extends GwtEvent<SelectionHandler> {
      * @return a {@link Type} identifier.
      */
     public static Type<SelectionHandler> getType() {
-        return eventType;
+        return EVENT_TYPE;
     }
 
     @Override
     public Type<SelectionHandler> getAssociatedType() {
-        return eventType;
+        return EVENT_TYPE;
     }
 
     @Override
diff --git a/client/src/main/java/com/vaadin/client/widgets/Grid.java b/client/src/main/java/com/vaadin/client/widgets/Grid.java
index 73867caa72..e134d01d9b 100755
--- a/client/src/main/java/com/vaadin/client/widgets/Grid.java
+++ b/client/src/main/java/com/vaadin/client/widgets/Grid.java
@@ -4702,7 +4702,7 @@ public class Grid<T> extends ResizeComposite implements HasSelectionHandlers<T>,
          */
         private final class DefaultTextRenderer implements Renderer<Object> {
             boolean warned = false;
-            private final String DEFAULT_RENDERER_WARNING = "This column uses a dummy default TextRenderer. "
+            private static final String DEFAULT_RENDERER_WARNING = "This column uses a dummy default TextRenderer. "
                     + "A more suitable renderer should be set using the setRenderer() method.";
 
             @Override