Use String.isEmpty()

44 files changed, 78 insertions, 78 deletions

diff --git a/client/src/main/java/com/vaadin/client/ApplicationConfiguration.java b/client/src/main/java/com/vaadin/client/ApplicationConfiguration.java
index 4c2583e493..0ee4a4f708 100644
--- a/client/src/main/java/com/vaadin/client/ApplicationConfiguration.java
+++ b/client/src/main/java/com/vaadin/client/ApplicationConfiguration.java
@@ -416,7 +416,7 @@ public class ApplicationConfiguration implements EntryPoint {
         JsoConfiguration jsoConfiguration = getJsoConfiguration(id);
         serviceUrl = jsoConfiguration
                 .getConfigString(ApplicationConstants.SERVICE_URL);
-        if (serviceUrl == null || "".equals(serviceUrl)) {
+        if (serviceUrl == null || serviceUrl.isEmpty()) {
             /*
              * Use the current url without query parameters and fragment as the
              * default value.
diff --git a/client/src/main/java/com/vaadin/client/BrowserInfo.java b/client/src/main/java/com/vaadin/client/BrowserInfo.java
index 1cbbb2145d..6e0b858990 100644
--- a/client/src/main/java/com/vaadin/client/BrowserInfo.java
+++ b/client/src/main/java/com/vaadin/client/BrowserInfo.java
@@ -197,13 +197,13 @@ public class BrowserInfo {
             }
 
             cssClass = prefix + browserIdentifier;
-            if (!"".equals(majorVersionClass)) {
+            if (!majorVersionClass.isEmpty()) {
                 cssClass = cssClass + " " + prefix + majorVersionClass;
             }
-            if (!"".equals(minorVersionClass)) {
+            if (!minorVersionClass.isEmpty()) {
                 cssClass = cssClass + " " + prefix + minorVersionClass;
             }
-            if (!"".equals(browserEngineClass)) {
+            if (!browserEngineClass.isEmpty()) {
                 cssClass = cssClass + " " + prefix + browserEngineClass;
             }
             String osClass = getOperatingSystemClass();
diff --git a/client/src/main/java/com/vaadin/client/SuperDevMode.java b/client/src/main/java/com/vaadin/client/SuperDevMode.java
index ce371c030d..e8eab082d1 100644
--- a/client/src/main/java/com/vaadin/client/SuperDevMode.java
+++ b/client/src/main/java/com/vaadin/client/SuperDevMode.java
@@ -184,7 +184,7 @@ public class SuperDevMode {
      *         SuperDevMode
      */
     protected static boolean recompileIfNeeded(String serverUrl) {
-        if (serverUrl == null || "".equals(serverUrl)) {
+        if (serverUrl == null || serverUrl.isEmpty()) {
             serverUrl = "http://localhost:9876/";
         } else {
             if (serverUrl.contains(":")) {
diff --git a/client/src/main/java/com/vaadin/client/VCaption.java b/client/src/main/java/com/vaadin/client/VCaption.java
index 0ed0bc037c..8da36becfa 100644
--- a/client/src/main/java/com/vaadin/client/VCaption.java
+++ b/client/src/main/java/com/vaadin/client/VCaption.java
@@ -207,7 +207,7 @@ public class VCaption extends HTML {
             String c = owner.getState().caption;
             // A text forces the caption to be above the component.
             placedAfterComponent = false;
-            if (c == null || c.trim().equals("")) {
+            if (c == null || c.trim().isEmpty()) {
                 // Not sure if c even can be null. Should not.
 
                 // This is required to ensure that the caption uses space in all
@@ -378,7 +378,7 @@ public class VCaption extends HTML {
             // Update caption text
             // A text forces the caption to be above the component.
             placedAfterComponent = false;
-            if (caption.trim().equals("")) {
+            if (caption.trim().isEmpty()) {
                 // This is required to ensure that the caption uses space in all
                 // browsers when it is set to the empty string. If there is an
                 // icon, error indicator or required indicator they will ensure
@@ -434,7 +434,7 @@ public class VCaption extends HTML {
                 setMaxWidth(maxWidth);
             } else {
                 String width = getElement().getStyle().getProperty("width");
-                if (width != null && !width.equals("")) {
+                if (width != null && !width.isEmpty()) {
                     setWidth(getRequiredWidth() + "px");
                 }
             }
diff --git a/client/src/main/java/com/vaadin/client/WidgetUtil.java b/client/src/main/java/com/vaadin/client/WidgetUtil.java
index d42ba541c6..c9e49f13c0 100644
--- a/client/src/main/java/com/vaadin/client/WidgetUtil.java
+++ b/client/src/main/java/com/vaadin/client/WidgetUtil.java
@@ -280,7 +280,7 @@ public class WidgetUtil {
 
     public static int setHeightExcludingPaddingAndBorder(Widget widget,
             String height, int paddingBorderGuess) {
-        if (height.equals("")) {
+        if (height.isEmpty()) {
             setHeight(widget, "");
             return paddingBorderGuess;
         } else if (height.endsWith("px")) {
@@ -307,7 +307,7 @@ public class WidgetUtil {
 
     public static int setWidthExcludingPaddingAndBorder(Widget widget,
             String width, int paddingBorderGuess) {
-        if (width.equals("")) {
+        if (width.isEmpty()) {
             setWidth(widget, "");
             return paddingBorderGuess;
         } else if (width.endsWith("px")) {
@@ -1477,7 +1477,7 @@ public class WidgetUtil {
             }
 
             s = s.trim();
-            if ("".equals(s)) {
+            if (s.isEmpty()) {
                 return null;
             }
 
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 ad5a33c02e..dca4ad7b3a 100644
--- a/client/src/main/java/com/vaadin/client/componentlocator/LegacyLocatorStrategy.java
+++ b/client/src/main/java/com/vaadin/client/componentlocator/LegacyLocatorStrategy.java
@@ -508,7 +508,7 @@ public class LegacyLocatorStrategy implements LocatorStrategy {
 
             if (part.equals(ROOT_ID)) {
                 w = RootPanel.get();
-            } else if (part.equals("")) {
+            } else if (part.isEmpty()) {
                 if (w == null) {
                     w = client.getUIConnector().getWidget();
                 }
diff --git a/client/src/main/java/com/vaadin/client/extensions/ResponsiveConnector.java b/client/src/main/java/com/vaadin/client/extensions/ResponsiveConnector.java
index 314d167bfe..f18ecb0711 100644
--- a/client/src/main/java/com/vaadin/client/extensions/ResponsiveConnector.java
+++ b/client/src/main/java/com/vaadin/client/extensions/ResponsiveConnector.java
@@ -350,7 +350,7 @@ public class ResponsiveConnector extends AbstractExtensionConnector
         // Loop through breakpoints and see which one applies to this width
         currentWidthRanges = resolveBreakpoint("width", width);
 
-        if (!"".equals(currentWidthRanges)) {
+        if (!currentWidthRanges.isEmpty()) {
             element.setAttribute("width-range", currentWidthRanges);
         } else {
             element.removeAttribute("width-range");
@@ -359,7 +359,7 @@ public class ResponsiveConnector extends AbstractExtensionConnector
         // Loop through breakpoints and see which one applies to this height
         currentHeightRanges = resolveBreakpoint("height", height);
 
-        if (!"".equals(currentHeightRanges)) {
+        if (!currentHeightRanges.isEmpty()) {
             element.setAttribute("height-range", currentHeightRanges);
         } else {
             element.removeAttribute("height-range");
diff --git a/client/src/main/java/com/vaadin/client/ui/AbstractComponentConnector.java b/client/src/main/java/com/vaadin/client/ui/AbstractComponentConnector.java
index 8623bc1d76..7ce3e5c9b7 100644
--- a/client/src/main/java/com/vaadin/client/ui/AbstractComponentConnector.java
+++ b/client/src/main/java/com/vaadin/client/ui/AbstractComponentConnector.java
@@ -771,10 +771,10 @@ public abstract class AbstractComponentConnector extends AbstractConnector
     public boolean hasTooltip() {
         // Normally, there is a tooltip if description or errorMessage is set
         AbstractComponentState state = getState();
-        if (state.description != null && !state.description.equals("")) {
+        if (state.description != null && !state.description.isEmpty()) {
             return true;
         }
-        return state.errorMessage != null && !state.errorMessage.equals("");
+        return state.errorMessage != null && !state.errorMessage.isEmpty();
     }
 
     /**
diff --git a/client/src/main/java/com/vaadin/client/ui/MediaBaseConnector.java b/client/src/main/java/com/vaadin/client/ui/MediaBaseConnector.java
index 9e457fa150..33624b8703 100644
--- a/client/src/main/java/com/vaadin/client/ui/MediaBaseConnector.java
+++ b/client/src/main/java/com/vaadin/client/ui/MediaBaseConnector.java
@@ -78,7 +78,7 @@ public abstract class MediaBaseConnector extends AbstractComponentConnector {
 
     private void setAltText(String altText) {
 
-        if (altText == null || "".equals(altText)) {
+        if (altText == null || altText.isEmpty()) {
             altText = getDefaultAltHtml();
         } else if (!getState().htmlContentAllowed) {
             altText = WidgetUtil.escapeHTML(altText);
diff --git a/client/src/main/java/com/vaadin/client/ui/VAbsoluteLayout.java b/client/src/main/java/com/vaadin/client/ui/VAbsoluteLayout.java
index 3ccdcdbee9..935706babd 100644
--- a/client/src/main/java/com/vaadin/client/ui/VAbsoluteLayout.java
+++ b/client/src/main/java/com/vaadin/client/ui/VAbsoluteLayout.java
@@ -429,7 +429,7 @@ public class VAbsoluteLayout extends ComplexPanel {
             if (css == null || !css.equals(position)) {
                 css = position;
                 top = right = bottom = left = zIndex = null;
-                if (!css.equals("")) {
+                if (!css.isEmpty()) {
                     String[] properties = css.split(";");
                     for (int i = 0; i < properties.length; i++) {
                         String[] keyValue = properties[i].split(":");
diff --git a/client/src/main/java/com/vaadin/client/ui/VAbstractTextualDate.java b/client/src/main/java/com/vaadin/client/ui/VAbstractTextualDate.java
index fd50c92aed..c9c6df01f4 100644
--- a/client/src/main/java/com/vaadin/client/ui/VAbstractTextualDate.java
+++ b/client/src/main/java/com/vaadin/client/ui/VAbstractTextualDate.java
@@ -207,7 +207,7 @@ public abstract class VAbstractTextualDate<R extends Enum<R>>
     @Override
     @SuppressWarnings("deprecation")
     public void onChange(ChangeEvent event) {
-        if (!text.getText().equals("")) {
+        if (!text.getText().isEmpty()) {
             try {
                 String enteredDate = text.getText();
 
diff --git a/client/src/main/java/com/vaadin/client/ui/VComboBox.java b/client/src/main/java/com/vaadin/client/ui/VComboBox.java
index 784f2b116d..93ac755ee1 100644
--- a/client/src/main/java/com/vaadin/client/ui/VComboBox.java
+++ b/client/src/main/java/com/vaadin/client/ui/VComboBox.java
@@ -1141,7 +1141,7 @@ public class VComboBox extends Composite implements Field, KeyDownHandler,
                         // stays selected
                         if (!"".equals(enteredItemValue)
                                 || selectedOptionKey != null
-                                        && !"".equals(selectedOptionKey)) {
+                                        && !selectedOptionKey.isEmpty()) {
                             doItemAction(potentialExactMatch, true);
                         }
                         suggestionPopup.hide();
@@ -1165,7 +1165,7 @@ public class VComboBox extends Composite implements Field, KeyDownHandler,
             } else {
                 // currentSuggestion has key="" for nullselection
                 if (currentSuggestion != null
-                        && !currentSuggestion.key.equals("")) {
+                        && !currentSuggestion.key.isEmpty()) {
                     // An item (not null) selected
                     String text = currentSuggestion.getReplacementString();
                     setText(text);
@@ -1867,7 +1867,7 @@ public class VComboBox extends Composite implements Field, KeyDownHandler,
             // when filtering, let the server decide the page unless we've
             // set the filter to empty and explicitly said that we want to see
             // the results starting from page 0.
-            if ("".equals(filter) && page != 0) {
+            if (filter.isEmpty() && page != 0) {
                 // let server decide
                 page = -1;
             } else {
@@ -1964,7 +1964,7 @@ public class VComboBox extends Composite implements Field, KeyDownHandler,
                     + suggestion.key + ")");
         }
         // special handling of null selection
-        if (suggestion.key.equals("")) {
+        if (suggestion.key.isEmpty()) {
             onNullSelected();
             return;
         }
@@ -2074,7 +2074,7 @@ public class VComboBox extends Composite implements Field, KeyDownHandler,
      */
     private void performSelection(String selectedKey, boolean forceUpdateText,
             boolean updatePromptAndSelectionIfMatchFound) {
-        if (selectedKey == null || "".equals(selectedKey)) {
+        if (selectedKey == null || selectedKey.isEmpty()) {
             currentSuggestion = null; // #13217
             selectedOptionKey = null;
             setText(getEmptySelectionCaption());
@@ -2357,7 +2357,7 @@ public class VComboBox extends Composite implements Field, KeyDownHandler,
         setText(text == null ? getEmptySelectionCaption() : text);
         setSelectedItemIcon(connector.getState().selectedItemIcon);
         selectedOptionKey = (connector.getState().selectedItemKey);
-        if (selectedOptionKey == null || "".equals(selectedOptionKey)) {
+        if (selectedOptionKey == null || selectedOptionKey.isEmpty()) {
             currentSuggestion = null; // #13217
             selectedOptionKey = null;
             updatePlaceholder();
diff --git a/client/src/main/java/com/vaadin/client/ui/VLabel.java b/client/src/main/java/com/vaadin/client/ui/VLabel.java
index f3d64108b4..3e596a21ab 100644
--- a/client/src/main/java/com/vaadin/client/ui/VLabel.java
+++ b/client/src/main/java/com/vaadin/client/ui/VLabel.java
@@ -50,7 +50,7 @@ public class VLabel extends HTML {
     @Override
     public void setWidth(String width) {
         super.setWidth(width);
-        if (width == null || width.equals("")) {
+        if (width == null || width.isEmpty()) {
             setStyleName(getElement(), CLASSNAME_UNDEFINED_WIDTH, true);
         } else {
             setStyleName(getElement(), CLASSNAME_UNDEFINED_WIDTH, false);
diff --git a/client/src/main/java/com/vaadin/client/ui/VOverlay.java b/client/src/main/java/com/vaadin/client/ui/VOverlay.java
index 5681df286f..4d0c8d2914 100644
--- a/client/src/main/java/com/vaadin/client/ui/VOverlay.java
+++ b/client/src/main/java/com/vaadin/client/ui/VOverlay.java
@@ -136,7 +136,7 @@ public class VOverlay extends Overlay {
             container.setId(id);
             String styles = ac.getUIConnector().getWidget().getParent()
                     .getStyleName();
-            if (styles != null && !styles.equals("")) {
+            if (styles != null && !styles.isEmpty()) {
                 container.addClassName(styles);
             }
             container.addClassName(CLASSNAME_CONTAINER);
diff --git a/client/src/main/java/com/vaadin/client/ui/VRichTextArea.java b/client/src/main/java/com/vaadin/client/ui/VRichTextArea.java
index 75bec94dca..b0f9a6a510 100644
--- a/client/src/main/java/com/vaadin/client/ui/VRichTextArea.java
+++ b/client/src/main/java/com/vaadin/client/ui/VRichTextArea.java
@@ -234,14 +234,14 @@ public class VRichTextArea extends Composite implements Field, KeyPressHandler,
     @Override
     public void setHeight(String height) {
         super.setHeight(height);
-        if (height == null || height.equals("")) {
+        if (height == null || height.isEmpty()) {
             rta.setHeight("");
         }
     }
 
     @Override
     public void setWidth(String width) {
-        if (width.equals("")) {
+        if (width.isEmpty()) {
             /*
              * IE cannot calculate the width of the 100% iframe correctly if
              * there is no width specified for the parent. In this case we would
diff --git a/client/src/main/java/com/vaadin/client/ui/VUpload.java b/client/src/main/java/com/vaadin/client/ui/VUpload.java
index a6d4875ec1..d25508d29a 100644
--- a/client/src/main/java/com/vaadin/client/ui/VUpload.java
+++ b/client/src/main/java/com/vaadin/client/ui/VUpload.java
@@ -59,7 +59,7 @@ public class VUpload extends SimplePanel {
             super.onBrowserEvent(event);
             if (event.getTypeInt() == Event.ONCHANGE) {
                 if (isImmediateMode() && fu.getFilename() != null
-                        && !"".equals(fu.getFilename())) {
+                        && !fu.getFilename().isEmpty()) {
                     submit();
                 }
             } else if (BrowserInfo.get().isIE()
diff --git a/client/src/main/java/com/vaadin/client/ui/colorpicker/AbstractColorPickerConnector.java b/client/src/main/java/com/vaadin/client/ui/colorpicker/AbstractColorPickerConnector.java
index e027775793..da08413926 100644
--- a/client/src/main/java/com/vaadin/client/ui/colorpicker/AbstractColorPickerConnector.java
+++ b/client/src/main/java/com/vaadin/client/ui/colorpicker/AbstractColorPickerConnector.java
@@ -50,7 +50,7 @@ public abstract class AbstractColorPickerConnector
             refreshColor();
 
             if (getState().showDefaultCaption && (getState().caption == null
-                    || "".equals(getState().caption))) {
+                    || getState().caption.isEmpty())) {
 
                 setCaption(getState().color);
             }
@@ -79,7 +79,7 @@ public abstract class AbstractColorPickerConnector
      */
     protected String getCaption() {
         if (getState().showDefaultCaption && (getState().caption == null
-                || "".equals(getState().caption))) {
+                || getState().caption.isEmpty())) {
             return getState().color;
         }
         return getState().caption;
diff --git a/client/src/main/java/com/vaadin/client/ui/combobox/ComboBoxConnector.java b/client/src/main/java/com/vaadin/client/ui/combobox/ComboBoxConnector.java
index 9d37afc8a5..2b3db9aa65 100644
--- a/client/src/main/java/com/vaadin/client/ui/combobox/ComboBoxConnector.java
+++ b/client/src/main/java/com/vaadin/client/ui/combobox/ComboBoxConnector.java
@@ -210,7 +210,7 @@ public class ComboBoxConnector extends AbstractListingConnector
                 page = 0;
             }
         }
-        int adjustment = getWidget().nullSelectionAllowed && "".equals(filter)
+        int adjustment = getWidget().nullSelectionAllowed && filter.isEmpty()
                 ? 1 : 0;
         int startIndex = Math.max(0,
                 page * getWidget().pageLength - adjustment);
diff --git a/client/src/main/java/com/vaadin/client/ui/orderedlayout/Slot.java b/client/src/main/java/com/vaadin/client/ui/orderedlayout/Slot.java
index 8755bea650..d8e0544aaf 100644
--- a/client/src/main/java/com/vaadin/client/ui/orderedlayout/Slot.java
+++ b/client/src/main/java/com/vaadin/client/ui/orderedlayout/Slot.java
@@ -538,7 +538,7 @@ public class Slot extends SimplePanel {
                 this.captionText.addClassName("v-captiontext");
                 caption.appendChild(this.captionText);
             }
-            if (captionText.trim().equals("")) {
+            if (captionText.trim().isEmpty()) {
                 this.captionText.setInnerHTML("&nbsp;");
             } else {
                 if (captionAsHtml) {
diff --git a/client/src/main/java/com/vaadin/client/ui/orderedlayout/VAbstractOrderedLayout.java b/client/src/main/java/com/vaadin/client/ui/orderedlayout/VAbstractOrderedLayout.java
index 1148ab90ad..d226e0b5dc 100644
--- a/client/src/main/java/com/vaadin/client/ui/orderedlayout/VAbstractOrderedLayout.java
+++ b/client/src/main/java/com/vaadin/client/ui/orderedlayout/VAbstractOrderedLayout.java
@@ -715,7 +715,7 @@ public class VAbstractOrderedLayout extends FlowPanel {
     @Override
     public void setHeight(String height) {
         super.setHeight(height);
-        definedHeight = (height != null && !"".equals(height));
+        definedHeight = height != null && !height.isEmpty();
     }
 
     /**
diff --git a/client/src/main/java/com/vaadin/client/ui/panel/PanelConnector.java b/client/src/main/java/com/vaadin/client/ui/panel/PanelConnector.java
index 5e22b9ef32..84ed73e537 100644
--- a/client/src/main/java/com/vaadin/client/ui/panel/PanelConnector.java
+++ b/client/src/main/java/com/vaadin/client/ui/panel/PanelConnector.java
@@ -96,7 +96,7 @@ public class PanelConnector extends AbstractSingleComponentContainerConnector
                     .setClassName(VPanel.CLASSNAME + "-deco");
             getWidget().captionNode.setClassName(VPanel.CLASSNAME + "-caption");
             boolean hasCaption = false;
-            if (getState().caption != null && !"".equals(getState().caption)) {
+            if (getState().caption != null && !getState().caption.isEmpty()) {
                 getWidget().setCaption(getState().caption);
                 hasCaption = true;
             } else {
diff --git a/server/src/main/java/com/vaadin/server/SizeWithUnit.java b/server/src/main/java/com/vaadin/server/SizeWithUnit.java
index b53e4533f4..b1b34e1fef 100644
--- a/server/src/main/java/com/vaadin/server/SizeWithUnit.java
+++ b/server/src/main/java/com/vaadin/server/SizeWithUnit.java
@@ -85,7 +85,7 @@ public class SizeWithUnit implements Serializable {
             return null;
         }
         s = s.trim();
-        if ("".equals(s)) {
+        if (s.isEmpty()) {
             return null;
         }
         float size = 0;
diff --git a/server/src/main/java/com/vaadin/server/VaadinServlet.java b/server/src/main/java/com/vaadin/server/VaadinServlet.java
index 0151d42b62..d2498dddfc 100644
--- a/server/src/main/java/com/vaadin/server/VaadinServlet.java
+++ b/server/src/main/java/com/vaadin/server/VaadinServlet.java
@@ -472,7 +472,7 @@ public class VaadinServlet extends HttpServlet implements Constants {
                 location.length() - lastPathParameter.length());
 
         if ((request.getPathInfo() == null || "/".equals(request.getPathInfo()))
-                && "".equals(request.getServletPath())
+                && request.getServletPath().isEmpty()
                 && !location.endsWith("/")) {
             /*
              * Path info is for the root but request URI doesn't end with a
diff --git a/server/src/main/java/com/vaadin/server/VaadinServletService.java b/server/src/main/java/com/vaadin/server/VaadinServletService.java
index 42213f60d0..1de9bfc1f4 100644
--- a/server/src/main/java/com/vaadin/server/VaadinServletService.java
+++ b/server/src/main/java/com/vaadin/server/VaadinServletService.java
@@ -152,7 +152,7 @@ public class VaadinServletService extends VaadinService {
         }
 
         String pathInfo = servletRequest.getPathInfo();
-        if (pathInfo != null && !"".equals(pathInfo)) {
+        if (pathInfo != null && !pathInfo.isEmpty()) {
             servletPath += pathInfo;
         }
 
@@ -272,7 +272,7 @@ public class VaadinServletService extends VaadinService {
             // Just ignore problem here
         }
 
-        if (appId == null || "".equals(appId) || "/".equals(appId)) {
+        if (appId == null || appId.isEmpty() || "/".equals(appId)) {
             appId = "ROOT";
         }
         appId = appId.replaceAll("[^a-zA-Z0-9]", "");
diff --git a/server/src/main/java/com/vaadin/ui/AbstractComponent.java b/server/src/main/java/com/vaadin/ui/AbstractComponent.java
index cce8d970dd..bea9ef9e56 100644
--- a/server/src/main/java/com/vaadin/ui/AbstractComponent.java
+++ b/server/src/main/java/com/vaadin/ui/AbstractComponent.java
@@ -195,7 +195,7 @@ public abstract class AbstractComponent extends AbstractClientConnector
      */
     @Override
     public void setStyleName(String style) {
-        if (style == null || "".equals(style)) {
+        if (style == null || style.isEmpty()) {
             getState().styles = null;
             return;
         }
@@ -222,7 +222,7 @@ public abstract class AbstractComponent extends AbstractClientConnector
 
     @Override
     public void addStyleName(String style) {
-        if (style == null || "".equals(style)) {
+        if (style == null || style.isEmpty()) {
             return;
         }
         if (style.contains(" ")) {
diff --git a/server/src/main/java/com/vaadin/ui/Embedded.java b/server/src/main/java/com/vaadin/ui/Embedded.java
index ef31790e8a..1f6c15e0c6 100644
--- a/server/src/main/java/com/vaadin/ui/Embedded.java
+++ b/server/src/main/java/com/vaadin/ui/Embedded.java
@@ -161,25 +161,25 @@ public class Embedded extends AbstractComponent implements LegacyComponent {
             target.addAttribute("src", getSource());
         }
 
-        if (mimeType != null && !"".equals(mimeType)) {
+        if (mimeType != null && !mimeType.isEmpty()) {
             target.addAttribute("mimetype", mimeType);
         }
-        if (classId != null && !"".equals(classId)) {
+        if (classId != null && !classId.isEmpty()) {
             target.addAttribute("classid", classId);
         }
-        if (codebase != null && !"".equals(codebase)) {
+        if (codebase != null && !codebase.isEmpty()) {
             target.addAttribute("codebase", codebase);
         }
-        if (codetype != null && !"".equals(codetype)) {
+        if (codetype != null && !codetype.isEmpty()) {
             target.addAttribute("codetype", codetype);
         }
-        if (standby != null && !"".equals(standby)) {
+        if (standby != null && !standby.isEmpty()) {
             target.addAttribute("standby", standby);
         }
-        if (archive != null && !"".equals(archive)) {
+        if (archive != null && !archive.isEmpty()) {
             target.addAttribute("archive", archive);
         }
-        if (altText != null && !"".equals(altText)) {
+        if (altText != null && !altText.isEmpty()) {
             target.addAttribute(EmbeddedConstants.ALTERNATE_TEXT, altText);
         }
 
diff --git a/server/src/main/java/com/vaadin/ui/Label.java b/server/src/main/java/com/vaadin/ui/Label.java
index c2fd132060..849e67ad63 100644
--- a/server/src/main/java/com/vaadin/ui/Label.java
+++ b/server/src/main/java/com/vaadin/ui/Label.java
@@ -141,7 +141,7 @@ public class Label extends AbstractComponent {
         } else {
             setContentMode(ContentMode.HTML);
         }
-        if (innerHtml != null && !"".equals(innerHtml)) {
+        if (innerHtml != null && !innerHtml.isEmpty()) {
             if (plainText) {
                 innerHtml = DesignFormatter.decodeFromTextNode(innerHtml);
             }
diff --git a/server/src/test/java/com/vaadin/server/LocaleServiceTest.java b/server/src/test/java/com/vaadin/server/LocaleServiceTest.java
index a93489194c..7742c2ae30 100644
--- a/server/src/test/java/com/vaadin/server/LocaleServiceTest.java
+++ b/server/src/test/java/com/vaadin/server/LocaleServiceTest.java
@@ -997,9 +997,9 @@ public class LocaleServiceTest {
     private static void generateData(Locale locale) {
         System.out.println();
         String id = locale.getLanguage();
-        if (!locale.getCountry().equals("")) {
+        if (!locale.getCountry().isEmpty()) {
             id += "_" + locale.getCountry();
-            if (!locale.getVariant().equals("")) {
+            if (!locale.getVariant().isEmpty()) {
                 id += "_" + locale.getVariant();
             }
         }
diff --git a/server/src/test/java/com/vaadin/tests/design/LocaleTest.java b/server/src/test/java/com/vaadin/tests/design/LocaleTest.java
index f1c61d9558..7673094ff1 100644
--- a/server/src/test/java/com/vaadin/tests/design/LocaleTest.java
+++ b/server/src/test/java/com/vaadin/tests/design/LocaleTest.java
@@ -93,19 +93,19 @@ public class LocaleTest {
         assertTrue(
                 "The element should not have a locale specification, found locale "
                         + eb1.attr("locale"),
-                "".equals(eb1.attr("locale")));
+                        eb1.attr("locale").isEmpty());
         Element eb2 = ehLayout.child(1);
         assertEquals("Wrong locale information.", "en_US", eb2.attr("locale"));
         Element ehLayout2 = evLayout.child(1);
         assertTrue(
                 "The element should not have a locale specification, found locale "
                         + ehLayout2.attr("locale"),
-                "".equals(ehLayout2.attr("locale")));
+                        ehLayout2.attr("locale").isEmpty());
         Element el1 = ehLayout2.child(0);
         assertTrue(
                 "The element should not have a locale specification, found locale "
                         + el1.attr("locale"),
-                "".equals(el1.attr("locale")));
+                        el1.attr("locale").isEmpty());
         Element el2 = ehLayout2.child(1);
         assertEquals("Wrong locale information.", "en_CA", el2.attr("locale"));
     }
diff --git a/shared/src/main/java/com/vaadin/shared/ui/ComponentStateUtil.java b/shared/src/main/java/com/vaadin/shared/ui/ComponentStateUtil.java
index 883ade868e..0ef247353b 100644
--- a/shared/src/main/java/com/vaadin/shared/ui/ComponentStateUtil.java
+++ b/shared/src/main/java/com/vaadin/shared/ui/ComponentStateUtil.java
@@ -29,16 +29,16 @@ public final class ComponentStateUtil implements Serializable {
     }
 
     public static final boolean isUndefinedWidth(AbstractComponentState state) {
-        return state.width == null || "".equals(state.width);
+        return state.width == null || state.width.isEmpty();
     }
 
     public static final boolean isUndefinedHeight(
             AbstractComponentState state) {
-        return state.height == null || "".equals(state.height);
+        return state.height == null || state.height.isEmpty();
     }
 
     public static final boolean hasDescription(AbstractComponentState state) {
-        return state.description != null && !"".equals(state.description);
+        return state.description != null && !state.description.isEmpty();
     }
 
     public static final boolean hasStyles(AbstractComponentState state) {
diff --git a/test/servlet-containers/generic/src/test/java/com/vaadin/tests/integration/AbstractIntegrationTest.java b/test/servlet-containers/generic/src/test/java/com/vaadin/tests/integration/AbstractIntegrationTest.java
index 6a948f63d8..10ad299a4b 100644
--- a/test/servlet-containers/generic/src/test/java/com/vaadin/tests/integration/AbstractIntegrationTest.java
+++ b/test/servlet-containers/generic/src/test/java/com/vaadin/tests/integration/AbstractIntegrationTest.java
@@ -87,7 +87,7 @@ public abstract class AbstractIntegrationTest extends ParallelTest {
 
     private String getDeploymentURL() {
         String deploymentUrl = System.getProperty("deployment.url");
-        if (deploymentUrl == null || deploymentUrl.equals("")) {
+        if (deploymentUrl == null || deploymentUrl.isEmpty()) {
             throw new RuntimeException(
                     "Deployment url must be given as deployment.url");
         }
diff --git a/testbench-api/src/main/java/com/vaadin/testbench/elements/AbstractComponentElement.java b/testbench-api/src/main/java/com/vaadin/testbench/elements/AbstractComponentElement.java
index e219b53a04..7a4963d4ab 100644
--- a/testbench-api/src/main/java/com/vaadin/testbench/elements/AbstractComponentElement.java
+++ b/testbench-api/src/main/java/com/vaadin/testbench/elements/AbstractComponentElement.java
@@ -36,7 +36,7 @@ public class AbstractComponentElement extends AbstractElement {
         captionId = getAttribute(GWT_ID_ATTRIBUTE);
         // IE8 getAttribute returns empty string instead of null
         // when there is no attribute with specified name
-        if (captionId == null || captionId.equals("")) {
+        if (captionId == null || captionId.isEmpty()) {
             WebElement elem = findElement(
                     By.xpath(".//*[@" + GWT_ID_ATTRIBUTE + "]"));
             captionId = elem.getAttribute(GWT_ID_ATTRIBUTE);
diff --git a/uitest/src/main/java/com/vaadin/tests/TestBench.java b/uitest/src/main/java/com/vaadin/tests/TestBench.java
index 076d02b4be..7de6e4e2c5 100644
--- a/uitest/src/main/java/com/vaadin/tests/TestBench.java
+++ b/uitest/src/main/java/com/vaadin/tests/TestBench.java
@@ -134,7 +134,7 @@ public class TestBench extends com.vaadin.server.LegacyApplication
                     public void uriFragmentChanged(
                             UriFragmentChangedEvent source) {
                         String fragment = source.getUriFragment();
-                        if (fragment != null && !"".equals(fragment)) {
+                        if (fragment != null && !fragment.isEmpty()) {
                             // try to find a proper test class
 
                             // exact match
diff --git a/uitest/src/main/java/com/vaadin/tests/components/TestBase.java b/uitest/src/main/java/com/vaadin/tests/components/TestBase.java
index 9a3906bdc0..9e638682ce 100644
--- a/uitest/src/main/java/com/vaadin/tests/components/TestBase.java
+++ b/uitest/src/main/java/com/vaadin/tests/components/TestBase.java
@@ -22,7 +22,7 @@ public abstract class TestBase extends AbstractTestCase {
         window.getContent().setSizeFull();
 
         Label label = new Label(getDescription(), ContentMode.HTML);
-        if (label.getValue() == null || "".equals(label.getValue())) {
+        if (label.getValue() == null || label.getValue().isEmpty()) {
             // This is only an ugly hack to be screenshot compatible to be able
             // to detect real problems when introducing IE font-size/line-height
             // fixes
diff --git a/uitest/src/main/java/com/vaadin/tests/components/popupview/PopupViewWithRTE.java b/uitest/src/main/java/com/vaadin/tests/components/popupview/PopupViewWithRTE.java
index 069ccef2bb..a411013ae3 100644
--- a/uitest/src/main/java/com/vaadin/tests/components/popupview/PopupViewWithRTE.java
+++ b/uitest/src/main/java/com/vaadin/tests/components/popupview/PopupViewWithRTE.java
@@ -30,7 +30,7 @@ public class PopupViewWithRTE extends TestBase {
             @Override
             public String getMinimizedValueAsHTML() {
                 String value = rte.getValue();
-                if (value == null || "".equals(value)) {
+                if (value == null || value.isEmpty()) {
                     value = "Initial <b>content</b> for <h3>rte</h3>.";
                     rte.setValue(value);
                     rte.setHeight("150px");
diff --git a/uitest/src/main/java/com/vaadin/tests/components/table/ItemClickEvents.java b/uitest/src/main/java/com/vaadin/tests/components/table/ItemClickEvents.java
index f5e62adfc8..1fbc932374 100644
--- a/uitest/src/main/java/com/vaadin/tests/components/table/ItemClickEvents.java
+++ b/uitest/src/main/java/com/vaadin/tests/components/table/ItemClickEvents.java
@@ -123,7 +123,7 @@ public class ItemClickEvents extends AbstractReindeerTestUI {
         if (event.isShiftKey()) {
             modifiers += "shift ";
         }
-        if (!"".equals(modifiers)) {
+        if (!modifiers.isEmpty()) {
             modifiers = " (" + modifiers.trim() + ")";
         }
 
diff --git a/uitest/src/main/java/com/vaadin/tests/components/ui/MultiFileUploadTest.java b/uitest/src/main/java/com/vaadin/tests/components/ui/MultiFileUploadTest.java
index 0533099a54..ffa9b55b3a 100644
--- a/uitest/src/main/java/com/vaadin/tests/components/ui/MultiFileUploadTest.java
+++ b/uitest/src/main/java/com/vaadin/tests/components/ui/MultiFileUploadTest.java
@@ -39,7 +39,7 @@ public class MultiFileUploadTest extends AbstractTestUIWithLog {
 
         @Override
         public void filenameChanged(ChangeEvent event) {
-            if (event.getFilename().equals("")) {
+            if (event.getFilename().isEmpty()) {
                 removeUpload(event.getSource());
             } else {
                 addUpload();
diff --git a/uitest/src/main/java/com/vaadin/tests/dd/DDTest5.java b/uitest/src/main/java/com/vaadin/tests/dd/DDTest5.java
index e932c02505..a5ad3c3f9c 100644
--- a/uitest/src/main/java/com/vaadin/tests/dd/DDTest5.java
+++ b/uitest/src/main/java/com/vaadin/tests/dd/DDTest5.java
@@ -147,7 +147,7 @@ public class DDTest5 extends TestBase {
 
                     String data = (String) dropEvent.getTransferable()
                             .getData("text/plain");
-                    if (data == null || "".equals(data)) {
+                    if (data == null || data.isEmpty()) {
                         data = "-- no Text --";
                     }
                     cssLayout.addComponent(new WrappedLabel(data));
diff --git a/uitest/src/main/java/com/vaadin/tests/themes/valo/ValoThemeUI.java b/uitest/src/main/java/com/vaadin/tests/themes/valo/ValoThemeUI.java
index 4ec83dc6ec..c4a50bf0d1 100644
--- a/uitest/src/main/java/com/vaadin/tests/themes/valo/ValoThemeUI.java
+++ b/uitest/src/main/java/com/vaadin/tests/themes/valo/ValoThemeUI.java
@@ -133,7 +133,7 @@ public class ValoThemeUI extends UI {
         navigator.addView("dragging", Dragging.class);
 
         String f = Page.getCurrent().getUriFragment();
-        if (f == null || f.equals("")) {
+        if (f == null || f.isEmpty()) {
             navigator.navigateTo("common");
         }
 
diff --git a/uitest/src/test/java/com/vaadin/tests/elements/treetable/TreeTableElementExpandRowTest.java b/uitest/src/test/java/com/vaadin/tests/elements/treetable/TreeTableElementExpandRowTest.java
index 49847ae0b6..e20a6dd4ab 100644
--- a/uitest/src/test/java/com/vaadin/tests/elements/treetable/TreeTableElementExpandRowTest.java
+++ b/uitest/src/test/java/com/vaadin/tests/elements/treetable/TreeTableElementExpandRowTest.java
@@ -48,7 +48,7 @@ public class TreeTableElementExpandRowTest extends MultiBrowserTest {
         TreeTableRowElement row = tree.getRow(rowIndex);
         WebElement cell = row.getCell(0);
         String errorMessage = "";
-        if (extraInfo != null && !extraInfo.equals("")) {
+        if (extraInfo != null && !extraInfo.isEmpty()) {
             errorMessage += extraInfo;
         }
         errorMessage += "Return value of row=" + rowIndex + " cell=0 should be "
diff --git a/uitest/src/test/java/com/vaadin/tests/tb3/AbstractTB3Test.java b/uitest/src/test/java/com/vaadin/tests/tb3/AbstractTB3Test.java
index 5985420c93..3d2c8e8481 100644
--- a/uitest/src/test/java/com/vaadin/tests/tb3/AbstractTB3Test.java
+++ b/uitest/src/test/java/com/vaadin/tests/tb3/AbstractTB3Test.java
@@ -771,7 +771,7 @@ public abstract class AbstractTB3Test extends ParallelTest {
         // Remove any possible URL parameters
         String pathWithoutQueryParameters = pathWithQueryParameters
                 .replaceAll("\\?.*", "");
-        if ("".equals(pathWithoutQueryParameters)) {
+        if (pathWithoutQueryParameters.isEmpty()) {
             return "ROOT";
         }
 
diff --git a/uitest/src/test/java/com/vaadin/tests/tb3/PrivateTB3Configuration.java b/uitest/src/test/java/com/vaadin/tests/tb3/PrivateTB3Configuration.java
index abee2c1c2c..aae9b3e13f 100644
--- a/uitest/src/test/java/com/vaadin/tests/tb3/PrivateTB3Configuration.java
+++ b/uitest/src/test/java/com/vaadin/tests/tb3/PrivateTB3Configuration.java
@@ -211,7 +211,7 @@ public abstract class PrivateTB3Configuration extends ScreenshotTB3Test {
     public static String getConfiguredDeploymentHostname() {
         String hostName = getProperty(HOSTNAME_PROPERTY);
 
-        if (hostName == null || "".equals(hostName)) {
+        if (hostName == null || hostName.isEmpty()) {
             hostName = findAutoHostname();
         }
 
@@ -232,7 +232,7 @@ public abstract class PrivateTB3Configuration extends ScreenshotTB3Test {
         String portString = getProperty(PORT_PROPERTY);
 
         int port = 8888;
-        if (portString != null && !"".equals(portString)) {
+        if (portString != null && !portString.isEmpty()) {
             port = Integer.parseInt(portString);
         }
 
diff --git a/uitest/src/test/java/com/vaadin/tests/tb3/TooltipTest.java b/uitest/src/test/java/com/vaadin/tests/tb3/TooltipTest.java
index d58eca573f..9c99818a96 100644
--- a/uitest/src/test/java/com/vaadin/tests/tb3/TooltipTest.java
+++ b/uitest/src/test/java/com/vaadin/tests/tb3/TooltipTest.java
@@ -91,7 +91,7 @@ public abstract class TooltipTest extends MultiBrowserTest {
     protected void checkTooltipNotPresent() throws Exception {
         try {
             WebElement tooltip = getTooltip();
-            if (!"".equals(tooltip.getText())
+            if (!tooltip.getText().isEmpty()
                     || tooltip.getLocation().getX() > -999) {
                 Assert.fail("Found tooltip that shouldn't be visible: "
                         + tooltip.getText() + " at " + tooltip.getLocation());
diff --git a/uitest/src/test/java/com/vaadin/v7/tests/components/grid/basicfeatures/server/GridColumnReorderTest.java b/uitest/src/test/java/com/vaadin/v7/tests/components/grid/basicfeatures/server/GridColumnReorderTest.java
index aac48dc4d2..bc10780ef6 100644
--- a/uitest/src/test/java/com/vaadin/v7/tests/components/grid/basicfeatures/server/GridColumnReorderTest.java
+++ b/uitest/src/test/java/com/vaadin/v7/tests/components/grid/basicfeatures/server/GridColumnReorderTest.java
@@ -253,7 +253,7 @@ public class GridColumnReorderTest extends GridBasicFeaturesTest {
         toggleColumnReordering();
         selectMenuPath("Component", "State", "Selection mode", "multi");
         List<TestBenchElement> gridHeaderRowCells = getGridHeaderRowCells();
-        assertTrue(gridHeaderRowCells.get(0).getText().equals(""));
+        assertTrue(gridHeaderRowCells.get(0).getText().isEmpty());
         assertColumnHeader("Column 0", gridHeaderRowCells.get(1));
         assertColumnHeader("Column 1", gridHeaderRowCells.get(2));
         assertColumnHeader("Column 2", gridHeaderRowCells.get(3));
@@ -263,7 +263,7 @@ public class GridColumnReorderTest extends GridBasicFeaturesTest {
 
         // then
         gridHeaderRowCells = getGridHeaderRowCells();
-        assertTrue(gridHeaderRowCells.get(0).getText().equals(""));
+        assertTrue(gridHeaderRowCells.get(0).getText().isEmpty());
         assertColumnHeader("Column 1", gridHeaderRowCells.get(1));
         assertColumnHeader("Column 0", gridHeaderRowCells.get(2));
         assertColumnHeader("Column 2", gridHeaderRowCells.get(3));
@@ -277,7 +277,7 @@ public class GridColumnReorderTest extends GridBasicFeaturesTest {
         selectMenuPath("Component", "State", "Selection mode", "multi");
         setFrozenColumns(1);
         List<TestBenchElement> gridHeaderRowCells = getGridHeaderRowCells();
-        assertTrue(gridHeaderRowCells.get(0).getText().equals(""));
+        assertTrue(gridHeaderRowCells.get(0).getText().isEmpty());
         assertColumnHeader("Column 0", gridHeaderRowCells.get(1));
         assertColumnHeader("Column 1", gridHeaderRowCells.get(2));
         assertColumnHeader("Column 2", gridHeaderRowCells.get(3));
@@ -287,7 +287,7 @@ public class GridColumnReorderTest extends GridBasicFeaturesTest {
 
         // then
         gridHeaderRowCells = getGridHeaderRowCells();
-        assertTrue(gridHeaderRowCells.get(0).getText().equals(""));
+        assertTrue(gridHeaderRowCells.get(0).getText().isEmpty());
         assertColumnHeader("Column 0", gridHeaderRowCells.get(1));
         assertColumnHeader("Column 2", gridHeaderRowCells.get(2));
         assertColumnHeader("Column 1", gridHeaderRowCells.get(3));
@@ -301,7 +301,7 @@ public class GridColumnReorderTest extends GridBasicFeaturesTest {
         selectMenuPath("Component", "State", "Selection mode", "multi");
         setFrozenColumns(-1);
         List<TestBenchElement> gridHeaderRowCells = getGridHeaderRowCells();
-        assertTrue(gridHeaderRowCells.get(0).getText().equals(""));
+        assertTrue(gridHeaderRowCells.get(0).getText().isEmpty());
         assertColumnHeader("Column 0", gridHeaderRowCells.get(1));
         assertColumnHeader("Column 1", gridHeaderRowCells.get(2));
         assertColumnHeader("Column 2", gridHeaderRowCells.get(3));
@@ -311,7 +311,7 @@ public class GridColumnReorderTest extends GridBasicFeaturesTest {
 
         // then
         gridHeaderRowCells = getGridHeaderRowCells();
-        assertTrue(gridHeaderRowCells.get(0).getText().equals(""));
+        assertTrue(gridHeaderRowCells.get(0).getText().isEmpty());
         assertColumnHeader("Column 1", gridHeaderRowCells.get(1));
         assertColumnHeader("Column 0", gridHeaderRowCells.get(2));
         assertColumnHeader("Column 2", gridHeaderRowCells.get(3));