The GWT Release Notes

Note - M1 = first milestone, RC1 = first release candidate

Release Notes for 2.11.0


  • Transitioned to GitHub pull requests for new contributions, with nightly builds running on GitHub Actions.
  • Added release artifacts for jakarta.servlet packages for both RequestFactory and GWT-RPC.
  • Tested support for running on Java 21. This is likely to be the final minor release series to support running on Java 8.
  • Disabled JPA/JDO “enhanced classes” serializable by default for GWT-RPC, and added a warning when it is in use.
  • Updated JRE emulation to support Java 11 for Collections, streams, and more.

Bug fixes:

  • Make custom field serializers ready for Java 17
  • Correctly write Long.toBinaryString as an unsigned value
  • Fix gzip encoding of responses in the CodeServer
  • Avoid EmptyStackException in SOYC
  • Fix error reporting for System.getProperty magic method nodes
  • Fix ClassNotFoundException when running JettyLauncher with Java 9+
  • Avoid StackOverflowError in TypeUtils#resolveGenerics
  • Avoid document.write in Chrome with iframe linker
  • Avoid document write in single script linker loading
  • Support intersection types in ternary expressions and var declarations
  • Fix for namespace=“” names that clash with variable names

JRE Emulation:

  • Added new Optional methods: or(), stream(), ifPresentOrElse(), empty(), and orElseThrow()
  • Added List/Set/Map of() methods
  • Added Predicate not() method
  • Added Collectors methods: flatMapping(), filtering(), toUnmodifiableList(), toUnmodifiableSet(), and toUnmodifiableMap()
  • Added Stream methods: dropWhile, takeWhile, and iterate(seed, hasNext, next)
  • Added Enumeration.asIterator()


  • Using DevMode as an application server is deprecated, and may be removed or changed in a future release. Please migrate local development workflows to using a general purpose server, or a custom ServletContainerLauncher.
  • The webAppCreator tool is deprecated, please refer to


  • Update chrome/firefox globals to latest
  • Updated Javadoc to run on Java 9+, support search
  • Removed unused scripts from old build wiring

For more detail, see the commit log.

Release Notes for 2.10.1


Release Notes for 2.10.0


  • Updated to HtmlUnit 2.55.0 and Jetty 9.4.44. With this newer HtmlUnit build comes support for Promise in unit tests, and the browser strings that can be specified when running tests are “FF”, “Chrome”, “IE” (for IE11), “Edge”, and “Safari”.

  • Tested support for running on Java 17, dropped remaining support for running on Java 7.

  • Maven groupId is formally changed to org.gwtproject, projects should take care to make sure they are using either the old BOM or the new org.gwtproject:gwt BOM to sure that Maven or Gradle correctly handle this change. This will be the last published version using the groupId.

  • Dropped support for IE 8, 9, and 10.

Bug fixes

  • Correct Long.hashCode semantics
  • Support CLASSPATH environment variable when creating child processes, fixing a bug where Windows could fail with a long list of arguments.
  • Use instead of displayName to support visible method names in Chrome 93+.
  • Allow stack traces to be available in Chrome when loading scripts from a remote origin.

JRE Emulation

  • Added OutputStreamWriter emulation.
  • Support StringReader mark() and reset() methods.
  • Added StrictMath emulation.
  • Added BufferedWriter emulation.
  • Added incomplete PrintStream emulation.
  • Add Charset.defaultCharset() emulation.
  • Improve BigInteger emulated performance.
  • System.nanoTime() emulation with
  • Added Optional.isEmpty emulation.
  • JRE Emulation improvements/simplifications to facilitate J2CL’s WASM support. Note that these do not always offer specific improvements to GWT itself, but helps to keep the codebases consistent.


  • Add support to compile GWT itself in Java 9+.
  • Improve compiled code size for applications that never use streams, by avoiding referencing streams from Throwable.

For more detail, see the commit log.

Release Notes for 2.9.0


  • Able to compile projects with jsinterop-base 1.0.0, elemental2 1.0.0, and jsinterop-annotations 2.0.0. With the exception of @JsAsync and @JsEnum, this brings GWT2 to be compatible across these tools with J2CL.

  • Added support for Java language levels 9, 10, and 11.

  • Officially, support is dropped for running the GWT compiler or server-side tooling on Java 7. The GWT distribution is still compiled to run on Java 7 for this release, but no guarantees are made about whether or not this will work. Future versions will compile bytecode for Java 8+. The release was tested and found to work cross platform when run with Java 8, 11, and 14.


  • Elemental has been officially deprecated - it is still included in this release, but may not appear in future releases. Instead, we encourage the use of the Elemental2 libraries, which are compatible with both GWT2 and J2CL.
  • Removed NoSuchMethodException emulation.

Bug fixes

  • Fixes Arrays.binarySearch semantics for float[] and double[]
  • Adds Support multi-line messages in errors/exceptions
  • Adds shutdown hook in DiskCache to clean up temp files
  • Cache Gecko version to lower CPU usage on FireFox
  • Do not assume that “this” is always non null.
  • Updates globals for Firefox version 60.0.2, Chrome 66.0.3359.45
  • Fixes String.regionMatches.
  • Native JsMethods allowed to coexist with implementations with the same name.
  • Make sure lambdas box, unbox and insert erasure casts when necessary.
  • Negative zero treated properly in Double/


  • Updates CLDR to version 34.
  • Arrays now implement Cloneable
  • Link backing errors together with a cause attribute, start tracking suppressed errors in addition to the cause in underlying error object.
  • Add AtomicReference to gwt/emul.
  • Propagate script nonces via ScriptInjector
  • Add partial emulation for ExecutorService and ScheduledExecutorService
  • Emulate java.util.concurrent.Flow
  • Emulate javax.annotation{,.processing}.Generated
  • Make sure “” is $wnd if not defined.
  • Add when-linker-added element definition
  • Add Reader and StringReader emulation.
  • Remove GWT version check.
  • Do not show “unusable-by-js” warning for synthetic methods.
  • Update unmodifiableList to throw on Java8 methods.
  • Disable DataflowOptimizer by default and emit a warning when used

For more detail, see the commit log.

Release Notes for 2.8.2


  • Supports running in Java 9. Note that this does not yet mean that GWT can compile Java 9 sources, or support the Java 9 JRE changes, but that a Java 9 JRE can be used to compile a GWT project. Do note that the new --module-path flag is not supported, but -classpath must still be used as in the past.

  • Chrome 61 removed functionality that had been used for reading the absolute top/left values. The internal implementation has been updated to reflect modern standards.

  • Uncaught exception handler will now receive all errors on the page, as handled by window.onerror. This may potentially be a breaking change if there were misbehaving scripts on the page. To disable this functionality, set the property gwt.uncaughtexceptionhandler.windowonerror to IGNORE:

    <set-property name="gwt.uncaughtexceptionhandler.windowonerror" value="IGNORE"/>

For more details, see

Bug fixes

  • LookupMethodCreator creates too large method
  • NativeRegExp should use iframe instance, fixing Edge JIT bug
  • JsProperty getter/setter sometimes were reported as incompatible
  • Instantiating native JsTypes from JSNI results in InternalCompilerException
  • Remove the SUBSIZED characteristic from filtered streams
  • Internal compiler exception when using native JsType varargs in a JsMethod
  • Regression in String.toLowerCase and toUpperCase for some locales, specifically for Turkish
  • Missing bounds check in String.charAt
  • Fix AIOOBE when compiling method references involving varargs.
  • Apply HtmlUnit workaround ensuring that window.onerror is called correctly


  • Migrated lang/jre emulation JSNI to JsInterop to share with J2CL
  • Added ErrorProne to gwt builds
  • Improved compliance with CSP
  • Added emulation for
  • Added emulation for java.lang.reflect.Array
  • JSO.equals/hashcode will delegate to the JS object if it has methods with those names
  • Removed outdated or unused parts of project
  • Migrate guava JRE emulation to GWT
  • HtmlUnit tests are now run in batch mode

For more detail, see the issue tracker and the commit log.

Release Notes for 2.8.1


  • Elemental1’s JSON parser now correctly throws an exception when a string, object, or array is not correctly ended

  • Support filtering JsInterop types for export, with whitelist/blacklist and wildcards. The -generateJsInteropExports flag is still used to enable the feature, but -includeJsInteropExports and -excludeJsInteropExports now exist to specify packages with optional * wildcards. Later arguments and patterns override earlier ones.

  • Support “*” (any) and “?” (unknown) types as a JsType native name. The “Unknown” type can be referred over Object if the type is unknown, while “any” is prefered supertype of any JS type, including primitives.

Bug fixes

  • Fix loading bug in waitForBodyLoaded.js
  • Fix NPE compiling code with a constructor reference (Type::new).
  • Fix bad rewriting of default methods.
  • Make native NativeRegExp refer to the iframe instance.
  • Fix incorrect comparison of object arrays in Arrays.deepEquals.
  • Fixed NullPointerException in handling of Jetty arguments
  • Fixes a bug where JsOptional on override may fail
  • Clear persistent unit cache when relevant options change.
  • Rescue JSOs crossing JsInterop borders.
  • Rescue types represented as natives when supertypes cross JS boundaries.
  • Prevent errorneous floating point expression optimization.
  • Fix the implementation of Stream.anyMatch/allMatch/noneMatch to support streams with null elements.
  • Do not ignore return values of streams.
  • Fix ICE due to intersection types appearing as erasure casts.
  • Fix bad varargs conversion in method reference.
  • Fix: Add role attribute to last sortable column header
  • Properly preserve names in overrides of native methods.
  • Make Array.sort(float[]/double[]) JDK compliant


  • Small optimization in String.subString
  • Specialize Objects.equals for strings.
  • Improve primitive cast optimizations.
  • Update global blacklist to chrome 57.0.2987.74.
  • Improvements for compliance with Strict CSP
  • Remove Characteristics manipulation in Collectors


  • Adds deprecation to @GwtScriptOnly

Release Notes for 2.8.0


  • Cleanup/update javadoc for jsinterop annotations.
  • Allow native classes implement native interfaces with overlays.

Release Notes for 2.8.0 (RC3)

Bug fixes

  • Fix erroneous constant propagation in JsProperty field.
  • Fix missing bridges for default methods and functionnal expressions.
  • Fix ArrayDeque’s bug when expanding capacity.
  • Fix missing declaration/initialization of JsOverlay fields.
  • Fix missing error reporting in SDM that leads to NPE.
  • Fix NullPointerException in super dev mode due to Boolean/Double/String devirtualization.
  • Fix generation of methods to access GSS constant in InterfaceGenerator.
  • Fix incorrect property copying for native JsType subclasses.
  • Fix toString dispatch for subtypes of native JsTypes.


  • Improve JsInterop error messages on native type fieds.
  • Update globals for Chrome 54.0.2840.16.


  • Deprecate dangerous RootPanel#clear(boolean).

Release Notes for 2.8.0 (RC2)

Bug fixes

  • Fix incorrect unusable-by-js warning.
  • Fix an issue around DevMode server (jetty) restart.
  • Fix an issue in super dev mode with changing compiler options not triggering full recompiles.
  • Added missing command line parameters to DevMode entry point
  • Fixed a performance regression in String.

Release Notes for 2.8.0 (RC1)


  • Partial support for Java 8 standard library APIs (see below for full list).
  • Fix memory leak with Java 8 compilation.
  • Source level set to Java 8.
  • Static and default methods in interfaces aren’t visible to generators. If you want to take advantage of those Java-8isms, you’re encouraged to switch to an annotation processor. This could break existing build if an interface is changed to turn a non-default method into a default method.


  • Classic dev mode deprecated.You can switch back to dev mode for your test cases temporarily by passing gwt.args=‘-devMode’.
  • Deprecate JSR 303 Bean Validation support (javax.validation, c.g.g.validation). The code hasn’t been maintained for years.

Breaking changes


  • Update JS reserved keywords to ES6.
  • Fix instanceof for primitives & string.
  • Make exceptions work across Java/JavaScript boundary
  • Allow casting native arrays to Object[].
  • Use patched JDT to circumvent memory leak when compiling for Java 8.


  • Implement @JsOverlay with default methods in Java8.
  • Disallow non-native @JsProperty on static methods.
  • Remove legacy JsInterop.
  • Add JsOptional annotation (disallowed on primitive typed parameters).
  • Allow @JsOverlay on effectively final methods.
  • Split JsInterop annotations into their own JAR when deploying to Maven:


  • Add support for JsType class in UIBinder.

JDK emulation

  • Emulate
  • Emulate Optional<T> and its int, long, double variants.
  • Emulate Objects.requireNonNull() with message Supplier.
  • Fix Math.min/max(float/double) emulation behavior.
  • Emulate Character.isBmpCodePoint().
  • Emulate CharSequence.chars().
  • Emulate java.lang.SecurityException.
  • Emulate Java 8 API of
  • java.util.Arrays,
  • java.util.ArrayDeque,
  • java.math.BigInteger,
  • java.util.BitSet,
  • java.util.Comparator,
  • java.util.function,
  • java.util.Iterator,
  • java.lang.Iterable,
  • java.util.IntSummaryStatistics/LongSummaryStatistics/DoubleSummaryStatistics
  • java.util.Collection/Lists/Queues,
  • java.util.Map,
  • java.util.logging.Logger,
  • java.util.PrimitiveIterator,
  • java.util.Spliterator,
  • java.util.StringJoiner


  • Add CSS3 and GSS support in InterfaceGenerator


  • Fixing up the Maven samples to work with GWT 2.8
  • Fixed spelling error when starting CodeServer
  • Update globals for Chrome 52.0.2743.24.
  • Update apache commons-collections to 3.2.2.
  • elemental.json.JsonValue is now serializable. This enables storing JsonValues in the HTTP session on the server.

Release Notes for 2.8.0 (Beta1)


  • Java 8 syntax supported.
  • JsInterop has graduated from experimental. See final JsInterop specification.
  • GSS is no longer considered as experimental and old CssResource is now deprecated.


  • Old CssResource syntax is now deprecated. For more information on GSS migration, please refer to this document

Compiler changes

  • Java 8 syntax is now supported by the compiler.
  • New optimizer framework that reruns the optimization process only on the part of the AST that were impacted by the changes since its last run. That speedup compilation of large application.
  • Added better type specialization that enables better optimizations.
  • Many bugfixes.

Library Changes

  • Generic Accessor for GWT Properties. You can now use System.getProperty() to access the value of any configuration or binding property at compile time.
  • Configurable Checks
  • Added -setProperty flag

JDK emulation

  • Started using ES6 Maps when available for HashMap/HashSet that yields up 3x performance improvements.
  • Switch to new long emulation with significant performance improvements (e.g. divisions 50x faster for smaller numbers)
  • Double/Boolean are not boxed anymore.

Logging and Stack Traces

  • Improved logging and stack traces for superdev mode.

GSS support

  • GSS is no longer experimental but it’s not enabled by default for easier and smoother migration to GWT 2.8. The CssResource.enableGss configuration property turns on GSS support. For more information on GSS migration, please refer to this document
  • “For loop support” added
  • a new function concat() is now available to concatenate variable and string literal.
  • @gen-webkit-keyframes annotation: generate automaticaly @-webkit-keyframes block

Dev Mode

  • Dev Mode is now deprecated

Super Dev Mode

  • SDM caches on disk the MinimalRebuildCache object, which speeds up the first SDM compile on a restart of the process.


For even more detail, see the Issue Tracker.

Release Notes for 2.7.0

This release fixes issues found while testing RC1.

For details, see the commit logs.

Known Issues

DevMode always starts in Super Dev Mode, so it’s not as easy to test in production mode. See issue 9004 for workarounds.

Release Notes for 2.7.0 (RC1)


  • Super Dev Mode is now the default. DevMode automatically starts Super Dev Mode and reloading a web page automatically runs the compiler when necessary. (The -nosuperDevMode flag may be used to revert to the old behavior.)

  • Compiling in Super Dev Mode is much faster after the first compile.

  • Experimental support for GSS, also known as Closure Stylesheets. (See below.)

Known Issues

  • gwttar files are incorrect. (Fixed in the next version.)


  • GWT Designer doesn’t work with 2.7 and is no longer supported. (Source code is available if someone wishes to revive this project.)

  • IFrameLinker and XSLinker are deprecated because they don’t work in Super Dev Mode. However, we don’t have suitable replacements for all use cases yet. For updates and possible workarounds, see issue 8997.

Compiler changes

  • In draft mode and Super Dev Mode, all compiler optimizations are turned off for better debugging. For example, null pointers are detected sooner.

  • JSNI references no longer require fully qualified class names when this wouldn’t be necessary in Java. (For example, imports work.)

  • We’ve started implementing JS Interop annotations, which will make it much easier to use GWT with JavaScript libraries. The specification is not final and there are bugs, so production GWT apps and libraries should continue to use JSNI for now. If you wish to experiment, you can enable JS Interop using the -XjsInteropMode flag, which is available for the compiler and Super Dev Mode. (It doesn’t work with old DevMode.)

  • The experimental -XmethodNameDisplayMode flag adds a displayName property to each JavaScript function containing the name of the Java method. This makes Java method names available in browser debuggers at the expense of code size. (Also available in Super Dev Mode.)

  • Boxed JavaScript strings (created in JavaScript using new String(...)) are no longer considered equivalent to Java strings. They should be unboxed before being passed to Java.

  • Many bugfixes.

Library Changes

JDK emulation

  • Significant performance improvements in String, ArrayList, HashMap, and Exception.

  • New emulated classes: Locale, NavigableSet, and NavigableMap.

  • New emulated methods in Class, String, Exception, RuntimeException, Logger, Arrays, Collections, and Map.Entry.

  • LinkedList extends Deque and handles incorrect usage better.

Logging and Stack Traces

  • Better wrapping of exceptions thrown from JavaScript.

  • GWT apps that inherit the module have different default behavior for messages logged using the java.util.logging package. The new default is to log messages at level SEVERE and above to the browser’s console. PopupLogHandler and SystemHandler are no longer enabled by default.

  • FirebugLogHandler and NullLoggingPopup have been removed. ()

Experimental GSS support

The CssResource.enableGss configuration property turns on GSS support.

  • When enabled, resource files with a ‘gss’ extension are parsed as a Closure Stylesheet.

  • When enabled, GSS can be used in a UiBinder file by setting gss="true" on a ui:style tag.

  • If the CssResource.legacy configuration property is set, .css resources and ui:style tags without gss=true will first be converted to GSS and then parsed as GSS.


  • The ui:data tag has new attributes: mimeType and doNotEmbed.


  • The rpc.XserializeFinalFields configuration property turns on experimental support for serializing final fields.

  • LinkedHashSet may be serialized without a serialization policy.

  • deRPC is removed.


  • Support overridden methods and generics better.

  • Fix support for @SkipInterfaceValidation on RequestContext methods.


  • Upgraded to CLDR 25.

Browser API changes

  • Updated support for typed arrays.

  • Added History.replaceItem().

  • Fixed an issue with Window.addWindowScrollHandler on Chrome.


  • The deprecated package is removed.

  • Various bugfixes and minor improvements.

Developer Tool Changes

Dev Mode

  • The -nosuperDevMode flag may be used to turn off Super Dev Mode and revert to old Dev Mode. (However, most current browsers no longer support Dev Mode plugins.)

  • The -modulePathPrefix flag may be used to move DevMode’s output to a subdirectory of the war directory.

Super Dev Mode

  • Compiling is much faster after the first compile. (Compiling is skipped altogether if no files have changed.)

  • The first compile no longer happens at startup.

  • Chrome reloads the page faster while debugging. (Sourcemap file size is reduced.)

  • The -launcherDir flag may be used to avoid running the GWT compiler before starting Super Dev Mode. When enabled, Super Dev Mode writes stub .nocache.js files that automatically recompile the GWT app before loading it. Therefore the bookmarklets aren’t needed. (This feature is automatically enabled when launched via DevMode.)

  • The -logLevel flag may be used to adjust how compile errors are reported.

  • The Dev Mode On bookmarklet dialog shows whether Super Dev Mode is turned on for each module on the page.

  • Messages logged using java.util.logging at level SEVERE and above are written to the browser console by default.

  • Fixed a startup failure caused by locked directories on Windows.


  • Better error reporting for compile errors while running tests.

  • Messages logged using java.util.logging at level SEVERE and above are written to the browser console and test output by default.

  • -Dgwt.htmlunit.debug may be used to open a JavaScript debugger window when running a test using HtmlUnit.

  • Removed RunStyleRemoteWeb and the BrowserManager tool.

  • Removed flags: -standardsMode, -nostandardsMode, -quirksMode. (GWTTestCase tests are always run in an HTML page in standards mode.)

For even more detail, see the Issue Tracker.

Release Notes for 2.6.1

This release contains bug fixes for GWT 2.6.0.


A complete list of changes can be found here.

Release Notes for 2.6.0

This release includes minor updates to silence unnecessary debugging warnings. See the release notes for 2.6.0 (RC1) for the full list of features and bugs fixes included in the GWT 2.6.0 release.

Release Notes for 2.6.0 (RC4)

This release enabled the Super Dev Mode hook by default, updated the sample Maven POMs, included a Firefox memory leak fix for Dev Mode, and a few other minor regressions noted during release candidate testing.

Release Notes for 2.6.0 (RC3)

This release fixed an incompatibility with the Google Plugin for Eclipse, improved uncaught exception handling, and reverted some backwards-incompatible changes made since GWT 2.5.1.

Release Notes for 2.6.0 (RC2)

This release disabled the Opera permutation, added a more maintainable DOM event dispatch mechanism, and fixed a few GWT-RPC and IE11 issues raised during release candidate testing.

Release Notes for 2.6.0 (RC1)


  • Java 7 is supported and is now the default. (This can be overridden using -sourceLevel 6)
  • GWT Development Mode will no longer be available for Chrome sometime in 2014, so we improved alternate ways of debugging. There are improvements to Super Dev Mode, asserts, console logging, and error messages.
  • Internet Explorer cleanup: IE6/7 support is disabled by default in this release and will be gone in the next major release. IE10 is now a separate permutation.

Compiler changes

  • A @GwtIncompatible annotation may be used to mark classes, methods, and fields that the GWT compiler should ignore. (Any annotation with this name can be used, regardless of package.)

Flag cleanup

Flags have been cleaned up for consistency, but the old flags are still supported for backward compatibility.

  • Arguments may be specified multiple times on the command line and the last one wins.
  • Boolean flags can consistently be disabled using ‘-no’.
  • Experimental flags consistently start with ‘-X’ or ‘-Xno’ to disable.
  • The deprecated -out flags were removed
  • Added flags for turning specific optimizations on and off.
  • The -saveSource and -saveSourceOutput *dest* options may be used to write source files used by the GWT app to an output directory. (Combined with the includeSourceMapUrl config property, it is possible to set up source-level debugging outside Super Dev Mode.)

Changes to generated JavaScript

  • Catching and rethrowing a JavaScript exception no longer wraps it in a Java exception (so the console will print it correctly, etc.)
  • Failed assertions stop in the browser’s debugger (if open)
  • Various code size improvements.

Code Splitting

  • Fragment merging is more reliable, works with soyc reports
  • GWT.runAsync: passing the same class is allowed, puts the code in the same fragment
  • GWT.runAsync always runs asynchronously; before it would sometimes be synchronous. (This behavior can be reverted by inheriting SynchronousFragmentLoadCallback.gwt.xml)
  • The compiler.splitpoint.leftovermerge.size configuration property sets a minimum size for fragments
  • AsyncProxy is deprecated
  • Various bugfixes

JavaScript Interoperability

  • JavaScriptObject: added createArray(size)
  • JsMixedArray: getString() fixed for nulls
  • JSNI: Allow line breaks (and other whitespace) within JSNI method references
  • JSNI: Don’t discard unary ‘+’ when it’s used to cast to a double issue 6373, 3942

Generator API

  • PropertyOracle: removed deprecated methods
  • JRawType.getImplementedMethods: fixed type parameters for inherited methods



JDK Emulation

  • java.lang.Class: added getSimpleName()
  • ArrayList.removeRange(): fixed
  • StringBuilder: added appendCodePointInt()
  • StringBuffer/Builder: added reverse()
  • Number subclasses:
    • integer parsing accepts initial ‘+’ (for Java 7 compatibility)
    • add compare methods (for Java 7)
    • fixed isFinite/isInfinite issue 8073
  • java.lang.reflect.Type: added
  • java.util.Objects: added (Java 7)
  • java.sql.Timestamp: fixed NullPointerException in equals() issue 6992

Core library fixes

  • GWT.debugger() emits a JavaScript debugger statement
  • GWT.maybeReportUncaughtException() sends an exception to the uncaught exception handler (if any)
  • About: cleaned up
  • ConsoleLogHandler: fixed for IE and Firefox issue 6916, issue 8040
  • Stack traces fixed on iOS.
  • Timer: cancel() fixed for IE6-8 issue 8101

Browser permutation changes

  • The ie6 permutation (which also handles IE 7) is now disabled by default. Support for IE6 and IE7 will be removed in the next major GWT release.

  • Added the ie10 permutation. There’s no fallback value, so deferred bindings and conditional CSS that explicitly checks user.agent may need to be updated. (However, note that workarounds needed for previous versions of IE may no longer be necessary.)

  • UserAgent: new class to access user.agent

Browser API changes

  • Element methods that return sizes in pixels automatically convert subpixel values to int (for backward compatibility).

  • All API’s that used to take (which has long been deprecated) now take a instead.

  • DOM methods that take a URL now accept a SafeUri object as well.

  • Node: added removeAllChildren()

  • Element: added toggleClassName()
  • Element.hasTagName() is now case-insensitive
  • Element subclasses: added is() methods, for example
  • user.client.DOM: deprecate old methods
  • KeyCodes: many more key codes, added isArrowKey()
  • HandlerRegistrations: added compose() method
  • Canvas: added drawImage() overloads, wrap() method
  • Animation: added isRunning()
  • DOM events not known to GWT can handled using Widget.addBitlessDomHandler(). This allows third-party libraries to handle events that GWT itself doesn’t know about (such as MsPointerEvents). issue 8379

HTML generation changes

  • HtmlElementBuilder: supports the <col> tag
  • HtmlBuilderFactory: return types are more specific
  • Builder methods that take a URL now accept SafeUri as well

CSS changes

  • @url now supports ImageResource
  • user.agent values have changed (see Browser permutation changes)

UiBinder changes

  • @UiHandler works with parameterized types issue 6091
  • @UiHandler works with bindery.event.shared.HandlerRegistration issue 7079

Widget changes

  • CellView: focus fix issue 8359
  • DataGrid fixes: style name, scroll bars issue 8309
  • DatePicker: lots of improvements.
  • DialogBox: fix auto-hide memory leak
  • FileUpload: fixed wrap() method issue 5055
  • HtmlTable,FlexTable,Grid: fixed memory leak in IE9/IE10 issue 6938
  • ListBox.setMultipleSelect undeprecated
  • MenuBar: focus fix issue 3884
  • RootPanel: added clear()
  • SimpleCheckBox: implement HasValue
  • SimplePager: added constructor to hide “first page” button
  • SingleSelectionModel: fixed getSelectedSet
  • SplitLayoutPanel: resizing fix issue 4755
  • SuggestBox:
    • changed to avoid firing events twice issue 3533
    • after selecting, move focus to the next field issue 8051
  • Tree/TreeItem: deprecated methods removed
  • ValueListBox: implement Focusable
  • ValuePicker: fixed setValue() to not fire events issue 7330


  • UiObject.setVisible() only adds aria-hidden for hidden objects


  • Document.{get,set}ScrollLeft(): fixed RTL for Safari and IE9
  • Plural rules updated for some Slavic languages
  • Fixed currency formatting when the currency symbol comes last (the symbol was added twice)
  • Number format constants upgraded to CLDR 21

Editor framework

  • CompositeEditor and subclasses take Editor<? super C>


  • Added support for Maps issue 5524
  • Added support for enums as type parameters in requests
  • Added support for EntityProxyId as a request parameter
  • Fixed a NullPointerException when server returns null issue 8104

Server-side classes

  • StackTraceDeobfuscator cleaned up and moved to gwt.core.server

Developer Tools

Developer Mode

  • Starts the user’s preferred browser on Linux
  • Fixed primitive class references in JSNI code (e.g. @int::class)
  • Reduced memory leakage

Super Dev Mode

  • Security: with 2.6 we believe it’s safe to turn on the Super Dev Mode hook and leave it on in production. As an extra precaution, we recommend setting the devModeUrlWhitelistRegexp configuration property to ensure that it can only load JavaScript from localhost and your developers’ machines in your own domain.

  • Security: automatically disable Super Dev Mode on https pages (Another precaution, and it doesn’t work anyway due to mixed-content restrictions.)

  • WebAppCreator now creates Ant projects with a “superdevmode” target and Super Dev Mode enabled.

  • Most sample apps have a “superdevmode” target
  • GWT.log() works and prints basic stack traces
  • sourceUrl comment fixed so that in a JavaScript debugger, the JavaScript source shows up as ‘{module}-0.js’ instead of just ‘0.js’.
  • Grey out unused Java in source code listings on the code server.
  • RemoteServiceServlet: the gwt.codeserver.port parameter may be used to download serialization policies from a Super Dev Mode code server’s /policies/ directory. This can be used to avoid some server recompiles when working on GWT-RPC code.


  • Benchmarking and Profile support removed
  • GWTTestCase reports better error messages in many cases
  • GWTTestCase: always use an UTF-8 HTML page
  • GWTTestCase: removed supportsAsync, addCheckpoint, clearCheckpoint, getCheckpoints
  • GWTTestCase now uses its own uncaught exception handler to avoid conflicts when testing code that calls GWT.setUncaughtExceptionHandler.

Upgraded dependencies

  • HtmlUnit 2.13
  • Jetty 8.1
  • Servlet 3.0
  • Guava 15.0
  • Protobuf 2.5.0
  • ASM 4.1
  • JDT 3.8.3
  • Closure compiler 20131014

For even more detail, see Changelists up to 2.6.0-rc1 and the issue tracker.

Release Notes for 2.5.1

This release includes an update to the sample application’s Maven POM files. See the release notes for 2.5.1 (RC1) for the full list of features and bugs fixes included in the GWT 2.5.1 release.

Release Notes for 2.5.1 (RC1)

GWT 2.5.1 is a maintenance release including many bugfixes and minor improvements since GWT 2.5.

Changes since 2.5.0

Security Fixes

  • Fixed an XSS vulnerability in html files used by GWTTestCase (patch). These files will only be included in a GWT app if it depends on the JUnit module. Despite the fix, this is not recommended.

Compiler and Linkers

  • Minor optimization improvements.
  • Optimization bugfixes: ( 5739, 7818, 7683).
  • Apps built with DirectInstallLinker should work in a page where inline scripts are forbidden (e.g. a Chrome extension)

Developer Mode

  • Fixed compatibility with OpenJDK 7.
  • Removed GWTShell, an obsolete way of starting dev mode.
  • Added a checkbox to automatically scroll the log.

Also, the Chrome plugin is now in the Chrome store.

Super Dev Mode

  • Added a -noprecompile option for faster startup.
  • Added support for IE8 (recompiles only, not debugging).
  • Reduced download size by using gzip.
  • Fixed an incompatibility with the debugger in Chrome 24+.
  • Fixed an incompatibility with third-party JavaScript that modifies the Array prototype.

Core libraries and JDK emulation

  • Changed Window.Location to return the new parameter values after a call to window.history.pushState
  • Added an option to ScriptInjector that removes the <script> tag from the page when done.
  • Added RequestBuilder.withCredentials().
  • Fixed a performance issue in RepeatingCommand (7307)
  • Fixed stack trace deobfuscation on iOS (7902)
  • Added the “webApiUsage” property. The default setting is “modern”. If set to “stable”, GWT libraries will avoid using prefixed web API’s. Currently, the only difference is that animation will use a timer. (7895)
  • Fixed Double.parseDouble() when called with Nan, Infinity, and leading zeros (7713, 7834)
  • Fixed Long.parseLong when called with MIN_VALUE (7308)
  • Fixed a bug in AbstractMap.remove (7856)

HTML, CSS, resource files

Widgets and Editors

  • Added Tree.setScrollIntoViewEnabled (2467)
  • Fixed a bug in SplitLayoutPanel.setWidgetHidden (7715)
  • Improved click handling in CellTable (7508)
  • Editor framework bugfixes: (5589, 6959)


  • Upgrades for ICU4J and CLDR
  • Fixed a bug in DateTimeFormat.parse() (7823)

RPC and server-side Java

  • Fixed incorrect GWT-RPC deserialization when an app is deployed after changing an enum and nothing else. (7836)
  • Fixed a GWT-RPC generator bug that can cause too many policy files to be generated, resulting in excessive server-side memory usage. (7791)
  • Fixed an infinite loop in server-side GWT-RPC when deserializing complicated generic types. (7779)
  • RequestFactory bug fix: (7900)
  • Added a constructor option to StackTraceDeobfuscator for conserving server memory.
  • Fixed an exception when using shared code that uses GWTBridge on the server (7527)

Release Notes for 2.5.0

This release includes some minor bug fixes found in the release candidate. See What’s New in GWT 2.5 plus the release notes for 2.5.0 (RC1) and 2.5.0 (RC2) for the full list of features and bugs fixes included in the GWT 2.5.0 release.

Security vulnerability from 2.4 to 2.5 Final

The GWT team recently learned that the Security vulnerability discovered in the 2.4 Beta and Release Candidate releases was only partially fixed in the 2.4 GA release. A more complete fix was added to the 2.5 GA release. If you have an app that’s been built with GWT 2.4 or one of the 2.5 RCs, then you’ll need to get the latest 2.5 release, recompile your app, and redeploy.

Release Notes for 2.5.0 (RC2)

This is release candidate 2 of GWT 2.5. See the What’s new in GWT 2.5 page as well as release notes below for the full list of features and bugfixes in this release.

Changes since RC1

  • The GWT tools can now run on JDK 7. (However, no JDK 7 language or library features are available in GWT code yet.)
  • The accessibility library introduced in RC1 has been cleaned up for release.
  • Support for validation is improved, documented, and no longer considered experimental.
  • Other fixes; see the issue tracker for more.

Release Notes for 2.5.0 (RC1)

This is release candidate 1 of GWT 2.5. See the What’s new in GWT 2.5 page as well as release notes below for the full list of features and bugfixes in this release.

Major Enhancements

  • Super Dev Mode, a replacement for Development Mode (experimental)
  • The Elemental library (experimental): efficient DOM access and HTML5 API’s (experimental)
  • New compiler optimizations from Closure
  • The fragment merging optimization, for reducing latency in large apps
  • Development mode performance and refresh time speedups
  • A new accessibility library for setting ARIA roles, states and properties on DOM elements
  • UIBinder enhancements for rendering cells and accessing inline styles

Other Fixes and Enhancements

  • Significant speedups in development refresh time as a result of generator result caching for the ClientBundle and RPC generators. Addition of a result caching API that generator writers can use (r10412, r10476).
  • Drastic improvement in RPC performance in development mode by providing a development-mode-only implementation for RPC.
  • Addition of source map support. See this document for more details.
  • Reduction of overhead of Java types in compiler output (r10435).
  • Addition of CellTableBuilder API, and an API for custom headers and footers in CellTables (r10435, r10581).
  • Addition of pre-deserialization type checking to reduce the number of error messages that occur from attempts to invoke an RPC method with type mismatches (r10518).
  • DynaTableRF and Validation samples now use Maven instead of ant.
  • DateCell now accepts a TimeZone as a constructor arg.
  • <ui:with> now supports the nested <ui:attribute> element for setting property values on a provided type (r10675).
  • Improvements in reporting of JavaScriptExceptions in development mode to include the method name and arguments.
  • Added ability to mock out Messages and CSSResources for better unit testing (r10723, r10768).
  • Added SafeHtml support to parts of the GWT user library.
  • CssResource @defs now support multiple values (r10667).
  • Added option to compile out logging calls below SEVERE and WARN (r10753).
  • CLDR data updated to v2.1.
  • Added simple and global currency patterns (r10742).
  • Update ISO-8601 time format to accept a timezone of a literal “Z” to mean GMT+0 (r10773).
  • Various fixes to stabilize the compiler output on null (no change) recompiles. Added the -Dgwt.normalizeTimestamps system property to zero out the date on output jar files to stabilize builds in build systems which rely on content-addressability (r10810).
  • Added GWT emulation for Float.intBitsToFloat, Float.floatToIntBits, Double.longBitsToDouble, and Double.doubleToLongBits.
  • Added support for typed arrays (r10839).
  • Greatly reduce symbol map size by removing already-pruned symbols from the map.
  • Allow absolute paths in ui:style’s src attribute.
  • Request methods that use Collections as parameters in RequestFactory’s JSON-RPC mode now properly encode Collections.

Breaking Changes and Other Changes of Note

  • If you previously linked against gwt-user.jar from pure Java code and now get ClassNotFoundExceptions, you may need to add gwt-dev.jar to your classpath as well.
  • Deprecated methods AbsractCellTable.doSelection(Event,Object,int,int), AbstractHasData.onUpdateSelection(), and CellList.doSelection(Event, Object, int) have been removed.
  • Major refactoring of IsRenderable API. See r10352 and r10421 for details.
  • The LEFT/RIGHT placement of text in SimplePager has been fixed, which may swap it for people who already worked around the issue. See r10907.
  • Tree[Item].addItem/insertItem(String html) have been deprecated due to potential XSS issues. Use Tree[Item].addTextItem/insertTextItem(String text) instead.
  • @GwtTransient will now work for any annotation that with that simple name (for example, This prevents library writers from having their library depend on the GWT distribution.
  • As part of the GWT compilation, an output file mapping full class names to CSS obfuscated names is generated. This is useful for debugging and testing (r10686).
  • Client-side JUnit classes are now available as a separate module without having to pull in GWTTestCase (r10689).
  • The permutation mapping file is now generated as part of every compile.
  • UIBinder.useLazyWidgets is now set to true by default. See r10730 for more details.
  • The following dependencies have been updated to the following versions:

    • Eclipse JDT 3.4.2_r894
    • Guava 10.0.1
    • HTMLUnit 2.9
    • Apache HTTP Client 4.1.2 (for HTMLUnit)
    • Apache Commons Lang 2.6 (for HTMLUnit)
    • NekoHTML 1.9.15 (for HTMLUnit)
  • json-1.5.jar is now bundled as a part of gwt-dev.jar. streamhtmlparser (rebased) has been removed from gwt-dev.jar and has been bundled as part of gwt-user.jar and gwt-servlet.jar.
  • The compiler metrics aspect of the Compile Report has been disabled by default. The compile report results in instability in the Compile Report. To add compiler metrics to the compilation report, use the -XcompilerMetrics flag.
  • The compiler.emulatedStack property should no longer be used. compiler.stackMode is what should be used instead.

In addition to the items mentioned above, see for a list of bug fixes and enhancements for 2.5.0 in the GWT issue tracker.

Known Issues

  • Clicking in the navigation area (but not on an actual item) of the Showcase sample results in the navigation area going blank.
  • Importing samples/Expenses into Eclipse fails with “Main Type Not Specified” dialog.
  • Mismatch in symbol map format between SpeedTracer and GWT results in SpeedTracer not being able to deobfuscate stack traces for GWT applications.

Release Notes for 2.4.0

This is the General Availability release of GWT 2.4. See the release notes below for the full list of features and bug fixes included in this release.

The 2.4 General Availability release of GWT contains new App Engine tools for Android, incremental RPC tooling, Apps Marketplace support, a faster UI Designer with better UiBinder support, a persistent unit cache for faster iterative development, a scrolling DataGrid with fixed header, Beans.isDesignTime() support, and bundled installers that make it easier to install and configure the GPE, GWT and GAE.

General Enhancements

  • App Engine tools for Android: Build installable Android apps that rely on App Engine for server-side support.
  • Incremental RPC Tooling: Add server-side methods to App Engine code and GPE will generate the necessary serialization and Android code on the fly.
  • Apps Marketplace Support: Deploy apps to the Google Apps Marketplace as easily as to App Engine.
  • UI Designer: Faster startup and editing times, split-mode editing support for UiBinder, simplified CSS property editing, UiBinder morphing, IsWidget support, and more.
  • Persistent Unit Cache: GWT Compiler and Development mode now cache compilation artifacts between runs. This results in faster startup time for iterative development.
  • Scrolling DataGrid (#188): The new DataGrid widget supports vertical scrolling with a fixed header (above) and footer (below).
  • Design Time Support (#226): The Beans.isDesignTime() method was added to the GWT emulation library in order to better isolate runtime-only code when a UI is edited in the UI Designer.

Noteworthy Fixed Issues

  • Polymorphism not supported by RequestFactory (#5367)
  • Support RequestFactory service inheritance on the client (#6234)
  • ListEditor subeditors’ value is not flushed when used with a RequestFactoryEditorDriver (#6081)
  • Memory-leak in pure-Java’s c.g.g.core.client.impl.WeakMapping (#6193)
  • GWT compiler dropping clinits (#5707)
  • Make RequestFactory type tokens more compact (#5394)
  • Editor framework does not support is / has methods (#6040)

See the complete list of bug fixes and enhancements for 2.4.0 in the GWT issue tracker.

See the complete list of breaking changes in the GWT issue tracker.

Security vulnerability in GWT 2.4

Recently, the GWT team discovered a cross-site scripting vulnerability in the 2.4 Beta and Release Candidate releases (not in v2.3 GA or v2.4 GA). This vulnerability was partially fixed in the 2.4 GA release and completely fixed in the 2.5 GA release. If you have an app that’s been built with 2.4 then you’ll need to get the latest 2.5 release, recompile your app, and redeploy.

Notes and Known Issues

  • GPE’s Maven support in Eclipse Indigo requires that the m2Eclipse WTP Integration plugin be installed. It can be installed via the JBoss Update site. See the Google Maven wiki page for the canonical reference for working with Maven in the latest GWT and GPE releases.
  • GWT’s new RequestFactory configuration is not enabled by default for plain GWT, App Engine, or GWT + App Engine projects. It is enabled by default for new Cloud-Connected Android Projects only. See the RequestFactoryInterfaceValidation wiki page for information on how to use the new RequestFactoryInterfaceValidator within Eclipse, Maven, or the command line.

Release Notes for 2.3.0

This is the General Availability release of GWT 2.3. See the release notes below for the full list of features and bug fixes included in this release.

General Enhancements

Noteworthy Fixed Issues

Known Issues

  • At compile time, you may see a warning similar to the following: “Configuration property UiBinder.useSafeHtmlTemplates is false! UiBinder SafeHtml integration is off, leaving your users more vulnerable to cross-site scripting attacks”. This warning occurs because although UiBinder HTML rendering has been updated to support SafeHtml, by default this is turned off (set to false), due to some minor bugs. If you wish, you can change the default by setting the “useSafeHtmlTemplates” property to true in UiBinder.gwt.xml. You can determine whether you are affected by the known bugs by checking the public bugs 6145, 6149, and 6198.

See the complete list of bug fixes and enhancements for 2.3.0 in the GWT issue tracker.

Release Notes for 2.3.0 (M1)

This is milestone 1 of GWT 2.3.

General Enhancements

  • Added the following functionality to the Google Plugin for Eclipse:

    • Google API integration
    • Project import from Google Project Hosting
    • Single sign on, for accessing Project Hosting and App Engine
  • Added GWT SDK support for HTML5 local storage

Noteworthy Fixed Issues

  • Updated GPE’s UIBinder editor to provide support for attribute auto-completion based on getter/setters in the owner type
  • Optimizations to speed up GPE launch configuration UI
  • “Check for Updates”, within GPE, will now detect updates to GWT and GAE SDKs
  • Launching against an external URL that contains a port number now works properly in Eclipse 3.6
  • Updated IE9 support (#5125)
  • Fixed iFrame loading issues within Internet Explorer (#1720)

See the complete list of bug fixes and enhancements for 2.3.0 M1 in the GWT issue tracker.

Release Notes for 2.2.0

The 2.2 release of GWT contains an integrated UI designer (part of the Google Plugin for Eclipse), support for HTML5 functionality, such as the Canvas/Audio/Video tags, an updated CellTable widget that now supports sortable columns and fixed column widths, and a more lenient SafeHtml template parser.

Also see What’s New in GWT 2.2?

General Enhancements

  • Touchstart, touchmove, touchend, touchcancel have been integrated into the GWT event framework (#5148)
  • Built-in bidi text support for widgets such as Label, HTML, Anchor, Hyperlink and ListBox. More information on this feature can be found here.

General Changes

  • GWT Designer v8.1.1 and earlier versions do not support GWT 2.2. To use GWT Designer with GWT 2.2, you need to uninstall the older version of GWT Designer and install the latest one.
  • Version 2.2 has deprecated support for Java 1.5, resulting in warnings when building applications. While Java 1.5 will still work for at least the next release of GWT, developers should upgrade their version of Java to correct these warnings and ensure compatibility with future versions of GWT.

Noteworthy Fixed Issues

  • RC releases are now being deployed as non-SNAPSHOTs in the maven repository (#5429)
  • Date/Time patterns are correct in the “sv” local (#5890)

See the complete list of bug fixes and enhancements for 2.2.0 M1, RC1 and final release in the GWT issue tracker.

Release Notes for 2.1.1

General Enhancements

  • Add a service layer to RequestFactory (#5111)

Noteworthy Fixed Issues

  • GPE flags <g:MenuItem> as an error (#5453)
  • Unable to disable a MenuItem (#1649)
  • No way to set vertical/horizontal alignment of Cells in CellTable (#5623)

See the GWT issue tracker for the complete list of bug fixes and enhancements in this release.

Release Notes for 2.1.0

This release includes some minor bug fixes found in the release candidate. See What’s New in GWT 2.1 plus the release notes for 2.1.0 (RC1) for the full list of features and bugs fixes included in the GWT 2.1.0 release.

Release Notes for 2.1.0 (RC1)

This is release candidate 1 of GWT 2.1.

Fixed Issues

  • Creation broken if the entity id is of type String (#1430)
  • addon-gwt is putting a boolean isChanged method in each proxy, and those don’t work (#1457)
  • ValueListBox showing redundant entries (#1287)
  • Implement new update / create / acquire / delete events (#1238)
  • Ensure that DefaultValueStore is always responsive (#1217)
  • Allow both String and Long keys (#951)
  • Does the mobile.user.agent property provider actually work? (#1468)
  • Banging on the UI can produce NPEs in DevMode window (#1282)
  • NPE on resume in AbstractRecordListActivity(#1230)
  • RequestFactoryServlet always throws when debugging with Chrome (#1229)
  • Implement java.math.BigDecimal support for GWT
  • Update the Expenses sample to pull dependencies in via a Maven repo (#991)
  • Add the custom Expense Report as a sample (#965)
  • Find replacement for velocity (#956)
  • Hard coded refusal to send fields named “password” in servlet (#1262)
  • No uncaught exception handler in scaffold app (#1250)
  • Remove web.xml welcome file handling from GWT addon (#1512)
  • Use a publicly accessible DTD for ApplicationCommon.gwt.xml (#1271)

Known Issues

  • RequestFactory does not fail gracefully for primitive types (5357)
  • Allow CellTable headers/footers to be refreshed (5360)
  • Need to document what situations source change events (5361)
  • Enable tests for RequestFactoryPolymorphicTest (5364)
  • Bring history management to Expenses sample (5366)
  • Polymorphism not supported by Request Factory (5367)
  • Server cannot return unpersisted objects (5374)
  • Javadoc polymorphism rules (5374)
  • Stopping an ActivityManager from a PlaceChangeEvent might cause an NPE (5375)
  • Why is gwt-servlet.jar a compile-time dependency in the pom.xml generated by the expenses.roo script? (5376)
  • Why does gwt-user.jar have scope “provided” in the pom.xml generated by the expenses.roo script? (5377)
  • Server side domain classes cannot be resolved (5378)
  • Confirm logging compiles out of generated scaffold apps (5379)
  • Many classes added in 2.1 still have the experimental API warnings in their javadoc that need to be removed (5380)
  • Showcase Cell List show {2} in entries with JDK 1.5 (5385)
  • Many stale javadoc warnings of experimental API (5380)
  • Instance methods are not looked up properly in the OperationRegistry (5425)

Release Notes for 2.1.0 (M3)

This is milestone 3 release of 2.1.

Fixed Issues

  • Add History support to the generated GWT scaffold app (#883)
  • Logging Implementation for M3 (#888)
  • Implement remaining primitive property types, including List and Long (#933)
  • Add enum support (#935)
  • Introduce setter methods for Record objects (#938)
  • Spec the minimum work needed for user auth, sign in (#955)
  • gwt project won’t import properly in eclipse with m2eclipse, has errors (#1122)
  • RequestFactoryServlet assumes content-length is known, which it may not be (#1150)
  • Selecting “Delete” from an entity in the Scaffold app takes you to a list view that contains no data. (#1164)
  • Allow client code to call instance methods (#1185)
  • Creates are clobbering existing records (#1194)
  • Update generated pom.xml to reference 2.1-SNAPSHOT jars (#1200)
  • Cleanup the implementation hack in DeltaValueStoreJsonImpl… (#1209)
  • Hard coded exit points for AbstractRecordEditActivity (#1225)
  • Hard coded exit points for AbstractRecordListActivity (#1226)
  • Can’t create child resources from AbstractRecordEditActivity anymore (#1227)
  • Update addon-gwt to reference GWT’s M3 repo (#1236)
  • GWT addon has links to MVC scaffolded view artifacts (#1249)
  • RootPanel.get(id) fails to set ‘position:relative’ and ‘overflow:hidden’ (#1813)
  • UncaughtExceptionHandler not triggered for exceptions occurring in onModuleLoad() (#1617)

Release Notes for 2.1.0 (M2)

This is milestone 2 release of 2.1.

Release Notes for 2.1.0 (M1)

This is a preview release of 2.1, that contains a new set of Cell Widgets and an app framework that make it easier to build large scale business applications.

Known Issues

  • For App Engine-based apps, you will need to run Maven once from the command line before importing the app into STS. This could be as simple as running “mvn validate” or “mvn compile”, the point is to prep your local repo with an unzipped GAE SDK.
  • Compiling a new app and/or running it in dev mode, will generate error messages complaining about missing dependencies. These errors can be ignored as they are related to classes that are most likely not used by your app, and will be omitted during compilation, or while running in dev mode.

Fixed Issues

  • Image.onload event does not fire on Internet Explorer when image is in cache (#863)
  • Image should provide method to set alternative text (#1333)
  • setWordWrap() for CheckBox (#1483)
  • RichTextArea - setEnabled does not work (#1488)
  • ImageSrc6 throws native NPE exception (#1700)
  • Array returned inside Serializable field causes ClassCastException in web mode (#1822)
  • BigDecimal Support (#1857)
  • When a MenuBar loses focus, the MenuItem remains selected (#2458)
  • KeyPressEvent contains improper UTF codes (#3753)
  • Make RemoteServiceRelativePath annotation RetentionPolicy.RUNTIME (#3803)
  • TextBox fires JSException in IE ((#4027)
  • Format number wrong result ((#4173)
  • file:line citations in ui.xml files (#4194)
  • Remove method in SplitLayoutPanel is broken (#4217)
  • Refactor SessionHandler and BrowserChannelClient to allow other OOPHM clients than HtmlUnit (#4287)
  • FinallyCommand scheduled from within another FinallyCommand sometimes gets stuck (#4293)
  • Wrong result after formatting of a big number in the NumberFormat (#4473)
  • Dictionary.keySet() contains "__gwt_ObjectId" in DevMode (#4486)
  • JsStackEmulator may break up JsInvocation (#4512)
  • DOMImpl.g/setInnerText() use unnecessarily expensive node manipulation (#4586)
  • NumberFormat error formatting more than 6 decimal places (#4598)
  • DateBox can generate an untrapped exception if a non-default format is used (#4633)
  • PopupPanel.removeFromParent() dosen’t remove glass panel (#4720)
  • ClassNotFoundException from web.xml for configured listeners during devmode servlet validation (#4760)
  • Converting ImageBundle to ResourceBundle causes a regression if bundle is used on the server side as well (#4797)
  • Add java.util.logging emulation ([#4954](#

Release Notes for 2.0.4

This 2.0.4 release contains fixes that were not included in the 2.0.3 release.

Noteworthy Fixed Issues

  • Whole UI disappear in IE 7 when we Hover over the menubar menu item (#4532)
  • List.subList not fully compatible with java.util.List interface (#4993)
  • Safari 5 fails to execute non-integral right-shifts correctly (#5056)

Release Notes for 2.0.3

This 2.0.3 release contains fixes that were not included in the 2.0.2 release.

Noteworthy Fixed Issues

  • Using a PopupPanel in Internet Explorer without a history IFrame throws a NullPointerException (#4584)
  • Opera support for History is not working (#3956)

Release Notes for 2.0.2

This 2.0.2 release contains a fix that was not included in the 2.0.1 release.

Noteworthy Fixed Issues

  • Standard.css missing new layout styles (#4429)

Release Notes for 2.0.1

This 2.0.1 release contains fixes for bugs found in the 2.0.0 release.

Potentially breaking changes and fixes

  • Fixed a bug in how code generators collect method arguments from generated source, which impacted the Messages interfaces generated for UiBinder template files. In GWT 2.0, such argument names were incorrectly changed to ARGn. Most GWT applications will be unaffected, but external systems relying on these names will need to be updated.
  • The development mode server will, by default, only bind to localhost which will break cross-machine debugging. You can get the old behavior by specifying -bindAddress Please see issue (#4322) for more details. For webAppCreator-generated ant files, you can pass this with ant -Dgwt.args="-bindAddress" devmode.
  • The CurrencyList/CurrencyData APIs are now public - if you were relying upon these classes in their non-public location, you should only need to update your imports.

Noteworthy Fixed Issues

  • UiBinder Image class with resource attribute, removes styles on that image (#4415)
  • Widgets lose focus if its placed on FocusPanel (Opera, Safari) (#1471)
  • Remove method in SplitLayoutPanel is broken (#4217)
  • Splitter constructor hard codes the background color of the splitter to white (#4335)
  • Image should provide method to set alternative text (#4335)
  • CssResource cannot parse unescaped ‘-’, ’_’ in class selectors and unknown at-rules (#3946)
  • Focusable implementation breaks ScrollPanels in Safari (#1313)
  • RequestBuilder restricted to GET and POST (#3388)
  • HTMLTable.Cell.getElement() calls getCellFormatter().getElement() with row and column swapped RequestBuilder restricted to GET and POST (#3757)
  • MenuBar steals focus when hovered (#3884)
  • TabLayoutPanel tabs don’t line up properly on IE (#4447)
  • webAppCreator produces ant build files which support the gwt.args property for passing additional flags to the gwtc and devmode rules, such as ant -Dgwt.args="-style PRETTY" gwtc.

See the GWT issue tracker for the complete list of bug fixes and enhancements in this release.

Release Notes for 2.0.0

This release includes some minor bug fixes found in the release candidate. See What’s New in GWT 2.0 plus the release notes for 2.0.0 (RC1) and 2.0.0-rc2 for the full list of features and bugs fixes included in the GWT 2.0.0 release.

Release Notes for 2.0.0 (RC2)

New Features

  <g:layer left='1em' width='20px'><g:Label>left-width</g:Label></g:Layer>
  <g:layer right='1em' width='20px'><g:Label>right-width</g:Label></g:Layer>
  • Window.Navigator now provides access to the native browser’s navigator object.

Breaking changes and known issues/bugs/problems

  • Windows users who have previously installed the GWT Developer Plugin for IE will have to uninstall the old version. Use the following steps:

    1. From the Windows “Start” Menu, open “Control Panel”
    2. Select “Add/Remove Programs”
    3. Select “GWT Developer Plugin for IE” then click “Uninstall”
    4. Run Internet Explorer and browse to to install the new version of the plugin
  • Running a GWTTestCase as compiled script was previously done using -Dgwt.args="-web". The -web argument is now deprecated in favor of -prod, consistent with the terminology change from web mode to production mode.
  • The -portHosted command line argument for DevMode and GWTTestCase has changed to -codeServerPort to be consistent with the new term code server.
  • The junitCreator command line utility has been removed. Instead, the webAppCreator utility takes new argument: -junit _<path-to-junit-jar>_ , which incorporates the functionality previously in junitCreator and generates ant test targets.
  • When running development mode on on Chrome, any JavaScript objects that pass into Java code will be assigned a new property __gwt_ObjectId. This could break native code that looks iterates through the properties of such an object. To work around this issue, see this example of our changes to JSONObject (scroll to the bottom).
  • Compile reports (formerly SOYC reports) are now generated with the -compileReport command line flag to Compiler. The generated reports are now written to the private extra directory. If no -extra argument is specified, this directory defaults to extras/. This eliminates an unlikely security risk of accidentally deploying compile reports to a publicly accessible location.

Fixed Issues

  • In UiBinder <ui:style> blocks, css class names may contain dashes.
  • Non-Java method safe characters in inline <ui:style> class names doesn’t work (#4052)
  • @external does not work reliably for inline styles in <ui:style> (#4053)
  • Various false alarm warnings about invalid JSNI references have been fixed.
  • Various Swing UI improvements.
  • RPC calls leaking memory for IE (#4133)
  • deRPC raise an Error 500 instead of propagating the correct RuntimeException in ProdMode (#4237)

Release Notes for 2.0.0 (RC1)

This release contains big changes to improve developer productivity, make cross-browser development easier, and produce faster web applications.

Things that are changing with GWT 2.0 that might otherwise be

confusing without explanation

  • Terminology changes: We’re going to start using the term “development mode” rather than the old term “hosted mode.” The term “hosted mode” was sometimes confusing to people, so we’ll be using the more descriptive term “development mode” from now on. For similar reasons, we’ll be using the term “production mode” rather than “web mode” when referring to compiled script.
  • Changes to the distribution: Note that there’s only one download, and it’s no longer platform-specific. You download the same zip file for every development platform. This is made possible by the new plugin approach used to implement development mode (see below). The distribution file does not include the browser plugins themselves; those are downloaded separately the first time you use development mode in a browser that doesn’t have the plugin installed.

Major New Features

  • In-Browser Development Mode: Prior to 2.0, GWT hosted mode provided a special-purpose “hosted browser” to debug your GWT code. In 2.0, the web page being debugged is viewed within a regular-old browser. Development mode is supported through the use of a native-code plugin called the GWT Developer Plugin for many popular browsers. In other words, you can use development mode directly from Safari, Firefox, Internet Explorer, and Chrome.
  • Code Splitting: Developer-guided code splitting with GWT.runAsync() allows you to chunk your GWT code into multiple fragments for faster startup. Imagine having to download a whole movie before being able to watch it. Well, that’s what you have to do with most Ajax apps these days – download the whole thing before using it. With code splitting, you can arrange to load just the minimum script needed to get the application running and the user interacting, while the rest of the app is downloaded as needed.
  • Declarative User Interface: GWT’s UiBinder now allows you to create user interfaces mostly declaratively. Previously, widgets had to be created and assembled programmatically, requiring lots of code. Now, you can use XML to declare your UI, making the code more readable, easier to maintain, and faster to develop. The Mail sample has been updated to show a practical example of using UiBinder.
  • Bundling of resources via ClientBundle. GWT introduced ImageBundle in 1.4 to provide automatic spriting of images. ClientBundle generalizes this technique, bringing the power of combining and optimizing resources into one download to things like text files, CSS, and XML. This means fewer network round trips, which in turn can decrease application latency – especially on mobile applications.
  • Using HtmlUnit for running test cases based on GWTTestCase: Prior to 2.0, GWTTestCase relied on SWT and native code versions of actual browsers to run unit tests. As a result, running unit tests required starting an actual browser. As of 2.0, GWTTestCase no longer uses SWT or native code. Instead, it uses HtmlUnit as the built-in browser. Because HtmlUnit is written entirely in the Java language, there is no longer any native code involved in typical test-driven development. Debugging GWT Tests in development mode can be done entirely in a Java debugger.

Breaking changes and known issues/bugs/problems

  • Prior to 2.0, GWT tools such as the compiler were provide in a platform-specific jar (that is, with names like gwt-dev-windows.jar). As of 2.0, GWT tools are no longer platform specific and they reside in generically-named gwt-dev.jar. You are quite likely to have to update build scripts to remove the platform-specific suffix, but that’s the extent of it.
  • The development mode entry point has changed a few times since GWT 1.0. It was originally called GWTShell, and in GWT 1.6 a replacement entry point called HostedMode was introduced. As of GWT 2.0, to reflect the new “development mode” terminology, the new entry point for development mode is Sorry to keep changing that on ya, but the good news is that the prior entry point still works. But, to really stay current, we recommend you switch to the new DevMode entry point.
  • Also due to the “development mode” terminology change, the name of the ant build target produced by webAppCreator has changed from hosted to devmode. In other words, to start development mode from the command-line, type ant devmode.
  • HtmlUnit does not attempt to emulate authentic browser layout. Consequently, tests that are sensitive to browser layout are very likely to fail. However, since GWTTestCase supports other methods of running tests, such as Selenium, that do support accurate layout testing, it can still make sense to keep layout-sensitive tests in the same test case as non-layout-sensitive tests. If you want such tests to be ignored by HtmlUnit, simply annotate the test methods with @DoNotRunWith({Platform.Htmlunit}).
  • Versions of Google Plugin for Eclipse prior to 1.2 will only allow you to add GWT release directories that include a file with a name like gwt-dev-windows.jar. You can fool it by sym linking or copying gwt-dev.jar to the appropriate name.
  • The way arguments are passed to the GWT testing infrastructure has been revamped. There is now a consistent syntax to support arbitrary “run styles”, including user-written, with no changes to GWT itself. For example, -selenium FF3 has become -runStyle selenium:FF3. This change likely does not affect typical test invocation scripts, but if you do use -Dgwt.args to pass arguments to GWTTestCase, be aware that you may need to make some changes.

Release Notes for 1.7.1

This release adds support for Mac OS X version 10.6 (Snow Leopard) by allowing hosted mode to run with a 1.6 JRE in 32-bit mode (using the -d32 flag).

Fixed Issues

  • Allow hosted mode using a 1.6 JRE with the -d32 flag (#3843, #3998)

Release Notes for 1.7.0

This release adds explicit support for Internet Explorer 8, Firefox 3.5, and Safari 4 as well as a few high-priority bug fixes. In all other respects, it is very similar to GWT 1.6. Note, however, that this release is version 1.7.0 rather than version 1.6.5 to signify a potentially breaking change for libraries that use deferred binding to specialize code based on user agent (see the next section for technical details).

Also see What’s New in 1.7?

Potentially breaking changes and fixes

  • This release includes explicit support for IE8, which has some significant behavioral changes from prior versions of IE. These changes are great enough that the new value ie8 has been added for the user.agent deferred binding client property. If you have deferred binding rules (i.e. <replace-with> or <generate-with>) or property providers that are sensitive to user.agent, you may need to update them to account for the ie8 value. For more information, see the technical notes.

Fixed Issues

  • Updated GWT libraries to support IE8 (#3558, #3329)
  • Native exception in (#3644)
  • Incorrect firing of two click events from CheckBox and a related issue (#3508, #3679)
  • Compiler java.lang.StackOverflowError if you don’t use -Xss to set a stack size (#3510)
  • Mouse wheel in FF3 (#2902)
  • GWT outputs expressions too long for WebKit (#3455)
  • java.sql.Date.valueOf error (#3731)
  • Added a workaround for Firefox 3.5 regression (bugzilla #497780)

Release Notes for 1.6.4

Fixed Issues

  • The classpath in the scripts created by junitCreator was updated to refer to /war/WEB-INF/classes rather than /bin.

Release Notes for 1.6.3 (RC2)

Fixed Issues

  • Various servlet classpath issues introduced in 1.6.2 are resolved.
  • JSP compilation should work out of the box in hosted mode.

Release Notes for 1.6.2 (RC)

Please see What’s new in GWT 1.6? (online)

Release Notes for 1.5.3

Fixed Issues

  • RPC requests no longer fail on the embedded Android web browser
  • Leaf TreeItems now line up with their non-leaf siblings
  • Removing the last child node from a TreeItem no longer creates extra margins on the left
  • HTTPRequest no longer uses POST instead of GET on some IE installs because of incorrect XHR selection
  • Compiler now uses a more reliable check to prevent methods with local variables from being inlined
  • getAbsoluteTop()/Left() can no longer return non-integral values
  • Time.valueOf() no longer fails to parse "08:00:00" or incorrectly accepts "0xC:0xB:0xA".

See the GWT issue tracker for the complete list of bug fixes and enhancements in this release.

Release Notes for 1.5.2

Potentially breaking changes and fixes

  • History.onHistoryChanged() has been added back (it was missing from 1.5 RC2) but is now deprecated. Application startup should be handled by calling the new History.fireCurrentHistoryState().
  • Fields marked final in serializable types will now generate a warning; the fact that they were not being serialized was a source of confusion. Mark such fields both final and transient to avoid the warning.
  • Instance methods on overlay types cannot be accessed from JSNI. (This used to work in hosted mode, but failed at runtime in web mode.)
  • The hosted mode server no longer serves hosted.html from a module’s public path; instead the file is read directly from the classpath. This file is tightly coupled with the hosted mode implementation and was not meant to be user overridable.

General Enhancements

  • Collections.unmodifiableSortedSet() and Collections.unmodifiableSortedMap() are now implemented.
  • The new Accessibility class enables widget authors to add ARIA support to their widgets. Many GWT widgets come with ARIA support by default.
  • Improved exception stack traces in hosted mode when JSNI stack frames are present.

Fixed Issues

  • Fixed the relationship between the coordinates returned by Element.getAbsoluteLeft/Top() and Event.getClientX/Y(). Document.getBodyOffsetLeft/Top() can be used to account for the difference between these two coordinate systems.
  • Ctrl-Z should correctly perform an undo operation in RichTextArea on IE.

See the GWT issue tracker for the complete list of bug fixes and enhancements in this release.

Release Notes for 1.5.1 (RC2)

Support for Standards Mode

GWT 1.5 adds significantly more support for standards mode applications, but some widgets (especially those with table based layouts) may not behave as expected. The low level standards mode bugs (such as with getAbsoluteLeft/Top() ) have been addressed, but some of the constructs that our widgets rely on do not work in standards mode. For example, you cannot set the height and width of a widget relative to its parent if its parent is a table cell, and StackPanel takes up much more vertical space than it should in Internet Explorer. All of our samples have been reverted back to quirks mode, and the applicationCreator defaults to quirks mode when creating a new GWT app.

You can still use standards mode for your GWT app, but please be aware that you may notice some layout issues. If you are switching an app from quirks mode to standards mode, your CSS styles might be applied differently, which could also affect your application. We will continue to address standards mode support in future GWT releases.

Potentially breaking changes and fixes

  • DOM.eventGetClientX/Y() now takes into account the margin and border of the body element
  • In hosted mode, all DOM.eventGetXXX() methods now assert that the requested attribute is reliable across all supported browsers. This means that attempting to retrieve an attribute for an event that does not support that attribute will now throw an assertion error instead of returning a coerced value. Most notably, the click event throws an assertion error if you attempt to get the mouse button that was clicked.
  • The return value of DOM.eventGetXXX() methods are now coerced to 0 instead of -1 in web mode. In hosted mode, an assertion error will be thrown if the attribute is not defined for the given event, as described in the previous bullet.
  • Opera specific code has been upgraded to work with Opera 9.5, but may not work with older versions of Opera as we only support the most recent release. Specifically, some widgets may not be able to receive focus.
  • Calls to History.newItem() now trigger an onHistoryChanged() event synchronously instead of asynchronously

General Enhancements

  • Added support for the contextmenu event, which allows users to detect and override the browser’s default context menu
  • Improved performance of NumberFormat
  • Added support for altering the number of decimals in a currency in NumberFormat
  • Improved performance of Animations
  • Improved the appearance of the default GWT style themes
  • Improved the Showcase sample with more robust examples and more language translations
  • FormPanel can now wrap an existing form and still submit it to a hidden iframe

Fixed Issues

  • DOM.getAbsoluteLeft/Top() and DOM.eventGetClientX/Y() no longer log an exception to the console in Firefox 3
  • Fixed a memory leak in Internet Explorer
  • DOM.getAbsoluteLeft/Top() now takes into account the margin and border of the target element in Safari 3
  • Fixed some bugs associated with history support

See the GWT issue tracker for the complete list of bug fixes and enhancements in this release.

Release Notes for 1.5.0 (RC)

This release candidate is, in a word, huge. Rather than including all the details here, please see What’s New in GWT 1.5? for full details. The main thing you’ll want to know is that GWT 1.5 supports the Java 5 language features (generics, enumerated types, annotations, etc.). But check out the full notes, because there’s a lot of great stuff!

Release Notes for 1.4.60

This release has only a couple of minor changes from 1.4.59.

  • Fixed a bug in the benchmarking that prevented source code from showing up in reports.
  • Fixed a bug in the hosted mode servlet context emulation where getResource() would fail to find a file in a module’s public path.
  • Compiler output files of the form _module_.cache.html used to contain html intended as a helpful note to a developer. This message has now been removed because screen readers and some browsers would display this content to end users.

Release Notes for 1.4.59 (RC2)

This release includes numerous bugfixes and a few important changes. If you are upgrading from GWT 1.3.3, you are strongly encouraged to read the release notes for 1.4.10 first.

New Features

General Changes

  • Startup is now faster and more reliable. In particular, onModuleLoad() is now called as soon as the DOM is ready, which will generally be before the page’s body.onload() event is fired. This allows your application to startup before certain resources (such as images) are fully loaded.
  • Linux hosted mode should be less crashy. (#1105, #1281, #1358)
  • An important discussion of HTTP headers, caching, and HTTPS has been added to the ImageBundle documentation. (#1172)
  • now causes the popup to be shown as well as centered. (#1120)
  • RichTextArea underwent number of bugfixes and should be stable now. (#1130, #1214, #1276)
  • New RPC warnings

    • Warn if a non-checked exception is used in the throws clause of a RemoteService method.
    • Warn if no concrete, serializable subclasses can be found for a given type declared in a RemoteService interface.
  • RPC now generates a serialization policy file during compilation. The serialization policy file contains a whitelist of allowed types which may be serialized. Its name is a strong hash name followed by .gwt.rpc. This file must be deployed to your web server as a public resource, accessible from a RemoteServiceServlet via ServletContext.getResource(). If it is not deployed properly, RPC will run in 1.3.3 compatibility mode and refuse to serialize types implementing Serializable. (#1297)
  • Panel.adopt(Widget, Element) and Panel.disown(Widget) have been deprecated. If you have subclassed Panel, please carefully review the new documentation for Panel.add(Widget) and Panel.remove(Widget) for details on the correct way to add and remove Widgets from Panels. (#1121)
  • The benchmark viewer application is now faster, prettier, and a bit more user friendly.

Retractions from 1.4.10

  • Breaking changes to the semantics of UIObject.setStyleName() have been backed out. All changes relative to 1.3.3 should now be backwards-compatible. (#1079)
  • The linux distribution of 1.4.10 bundled Mozilla 1.7.13 instead of version 1.7.12, which is bundled in previous releases. This change caused problems on some systems, so it’s been reverted back to Mozilla 1.7.12 again. (#1105)
  • Numerous RPC warnings were added in 1.4.10. One of these warnings would be issued when a class containing native methods was found to be serializable. This warning now only applies to automatically serialized types; types with custom serializers will no longer trigger this warning. (#1161)
  • A change to RPC in 1.4.10 would cause an error to be issued if a serializable type had any subtypes that were not serializable. This change caused code that worked in 1.3.3 to fail in 1.4.10. In this release, the error has been downgraded to a warning. (#1163)
  • A potentially breaking change to event bubbling in 1.4.10 has been backed out in favor of the 1.3.3 behavior. (#1159)

Fixed Issues

See the GWT issue tracker for the complete list of bug fixes in this release.

Release Notes for 1.4.10 (RC)

This is the Release Candidate for GWT 1.4, the first GWT release developed with major participation from GWT open source contributors. It’s been a long time coming, but we hope it’s been worth the wait. In addition to tons of new features, optimizations, and performance enhancements, we’ve fixed more than 150 bugs. There are some important behavioral and potentially breaking API changes; if you read nothing else, please read these following sections!

Behavioral Changes

Important changes in the behavior of existing GWT features.

Critical Changes to RPC

In previous versions, the RPC subsystem was too lenient and failed to warn at compile time about potential (though unusual) edge cases that could in theory cause problems at runtime. Beginning with version 1.4, the RPC subsystem emits additional warnings and errors to help you identify error-prone constructs. While this new behavior may seem annoying at first, rest assured that fixing your code to avoid RPC warnings will result in a smaller, faster, and more reliable app.

  • Bad code that happened to work before might not now

    Previously, if you declared one particular component type via @gwt.typeArgs at compile time, you could often get away with passing a different type at runtime. For example, placing a Date in an ArrayList of String might work. This type of code is less likely to work now and will likely become more strict in the future. Bottom line: don’t do this. Make sure collections only contain the declared item type (or subtypes thereof).

  • Serializable equivalent to IsSerializable

    Although GWT’s RPC mechanism doesn’t purport to honor the semantics of Java serialization, by popular demand, Serializable and IsSerializable are now equivalent for the purposes of RPC. This should improve server-side interoperability and remove much of the need for DTOs.

  • Warn about missing gwt.typeArgs Every Collection or Map type should have an associated gwt.typeArgs javadoc annotation. In the past, a missing @gwt.typeArgs would generally have no noticeable effect, because a bug in the RPC system would generate code for all available serializable types, even if they weren’t used in your service interface. Now that this bug has been fixed, you can achieve significant reduction in the size of your compiled output by fixing these warnings.
  • Warn about serializable subclasses that violate the serialization restrictions An RPC warning is emitted for classes that are assignable to IsSerializable or Serializable but that lack a default constructor or contain fields which cannot be serialized. It is important to resolve these warnings to avoid rare but confusing situations in which exceptions would be thrown at runtime.
  • Warn about non-transient, final instance fields

    RPC has never actually serialized final instance fields, but now it explicitly warns about the existence of such fields unless they are also transient. Thus, the warning can be addressed by making final instance fields transient as well, or it can be suppressed via a module property.

  • Warn about local and non-static nested types that implement IsSerializable or Serializable RPC has never serialized these kinds of classes and will now generate a warning.
  • Warn about native methods in serializable classes

    Attempting to serialize classes that contain native methods will cause UnsatisfiedLinkErrors if such methods are called in server-side code.

Module Script Tags

  • In previous versions of GWT, including external JavaScript files via a module <script> tag required a nested JavaScript expression — called a script-ready function — that would determine when the script had been successfully loaded. Script load order is now handled automatically and these expressions are ignored. A warning will be issued in hosted mode. For reference, see here.

Additional Hosted Mode Checks Related to JSNI

  • Previously, when passing values from JavaScript into Java, hosted mode would silently coerce a JavaScript value of an incorrect type into the declared Java type. Unfortunately, this would allow code to work in hosted mode that could fail in unexpected ways in web mode. Hosted mode will now throw a HostedModeException if you try to pass an incompatible type. See here for more details.

Breaking API Changes

This release also includes API changes that may require minor tweaks to existing code. Any such changes that affect you should only take a few minutes to rectify.

#### JavaScriptObject

  • Although subclassing JavaScriptObject is not supported, some people do so anyway at their own risk :) Please note that the existing (int) constructor has been removed in favor of a protected no-arg constructor. Read the source code for Element for an example of how JavaScriptObject must be subclassed now (that is, if subclassing were supported…which, of course, it isn’t).

#### DeferredCommand

  • The add() method is deprecated in favor of addCommand() in order to support the new IncrementalCommand interface. Had we simply added a new method overload, existing code that passed in a null literal would have failed to compile.
  • The new addPause() method should be used instead of add(null).

#### UIObject

  • The intended use and behavior of style names has been formalized in UIObject (and therefore in all widgets). All style names are now classified as “primary”, “secondary”, and “dependent” styles, the meanings of which are detailed in the UIObject documentation. The relevant method signatures remain unchanged (get/setStyleName(), add/removeStyleName()), and most widgets should be unaffected. One potentially breaking change, however, is that an exception is thrown if an attempt is made to remove the primary style name of a widget using removeStyleName(). See the UIObject documentation for a full explanation.

New Features

Here are a few of the coolest new features and enhancements in GWT 1.4.

  • Size and Speed Optimizations

    • New size improvements in the GWT compiler produce JavaScript that is 10-20% smaller; just recompile your app with 1.4.
    • An enhanced startup sequence reduces the size of your module’s startup script by 80%. More importantly, the new startup sequence removes an HTTP round-trip, making startup latency about 33% faster.
    • The above optimizations combined with ImageBundle, make it possible for GWT-based applications to load surprisingly quickly. To see for yourself, check out startup time of the Mail sample.
  • Deployment Enhancements

    • GWT RPC is no longer tied to exclusively to servlets. New modularized RPC server code makes it easy to connect GWT RPC to your choice of Java back-ends.
    • Adding GWT modules to an HTML page has been simplified. Instead of adding a <meta name='gwt:module'> and <script src='gwt.js'>, you just add a single script element for your module.
    • Cross-site script inclusion is now supported. The compiler produces a “-xs” (meaning “cross-site”) version of your module’s startup script that can be included without being restricted by the same-origin policy. WARNING: including scripts from other sites that you don’t fully trust is a big security risk.
  • Widget and Library Enhancements

    • RichTextArea allows “drop in” functionality for rich text editing.
    • SuggestBox makes it easy to add auto-complete functionality.
    • Splitters! HorizontalSplitPanel and VerticalSplitPanel enable you to resize portions of the user interface.
    • PushButton and ToggleButton are easy-to-customize button widgets that can enhance the look-and-feel of your UI.
    • DisclosurePanel is a simple, nice-looking panel that lets users easily hide and show portions of your application UI.
    • DateTimeFormat and NumberFormat make it easy to format and parse dates, times, and numbers for users all over the world.
    • IncrementalCommand helps you implement long-running tasks in your client code without triggering “slow script” warnings.
    • A new benchmarking subsystem integrates with JUnit to let you record and compare the speed of code snippets across multiple browsers and multiple parameter ranges. Benchmarking is a powerful way to identify bottlenecks and compare performance of alternative implementations.
    • The oft-requested is now included in the JRE emulation library and is synonymous with IsSerializable for the purpose of GWT RPC.
    • Mouse wheel events are now available on a variety of widgets.
  • ImageBundle

    • ImageBundle is the single biggest have-to-see-it-to-believe-it feature in this release. Image bundles make it trivially easy to combine dozens of images into a single “image strip”, collapsing what would have been dozens of HTTP requests into one: a single, permanently-cacheable image file.
    • Image bundles manage everything for you automatically, from computing clipping rectangles to making transparent PNGs work in IE6. You can even choose to get the clipped image as an Image widget or as pure HTML for inclusion in a larger HTML template.
    • In addition to enabling a blazing-fast startup, image bundles help make the UI look better during startup, too. Typical AJAX apps exhibit “bouncy relayout” as individual images are loaded one-at-a-time. Fixing this problem has historically required laboriously pre-initializing the width and height of each individual image ahead of time. Image bundles do the same thing automatically. The dimensions of each clipped image are computed at compile time while the bundled image file is being created. Voila! The result is a fast, non-ugly user startup experience that requires no extra work on the part of the GWT developer to keep up-to-date.
    • See the doc section for more details.

See the GWT issue tracker for the complete list of enhancements in this release.

Fixed Issues

See the GWT issue tracker for the complete list of bug fixes in this release.

Release Notes for 1.3.3

This version has only minor functional changes from 1.3.1, listed below.

Fixed Issues

Release Notes for 1.3.1 (RC)

This is the Release Candidate for GWT 1.3, the first completely open source version of GWT. This version has no new functionality, but we did make a lot of changes to get the source code and build scripts into presentable shape to prepare for ongoing open source development. Although the changes were relatively harmless – formatting, sorting, more documentation, and a new build system – there’s always a small chance of problems, so we plan to call this a Release Candidate until we’ve convinced ourselves it’s reliable.

Useful Links

  • Making GWT Better This is our new GWT open source charter that describes how we plan to operate the project and how you can access the GWT source, compile it yourself, and contribute.
  • The GWT Issue Tracker Please report any bugs in 1.3 RC that weren’t in 1.2.22 in the GWT issue tracker. These would be likely related to the new build, and we want to know ASAP so we can fix them.
  • The GWT Git Repository Visit the online repository to browse the GWT source without a Git client.

Release Notes for 1.2.22

This is the official GWT 1.2 release, the follow up to the GWT 1.2 Release Candidate. It includes all of the enhancements and bug fixes from GWT 1.2 RC as well as a few additional bug fixes that were reported against GWT 1.2 RC.

About OS X Hosted Mode Support

GWT’s hosted mode support is available only on OS X 1.4 (Tiger) or later.

Useful Links

Breaking API Changes

There are no breaking changes to pre-1.2 APIs, but one method has been renamed in a class that was new in 1.2 RC.

The method addHeader() was renamed to setHeader() to more clearly reflect its intent. You will only be affected by this change if you are using the new HTTP functionality available as of build 1.2.11.

Release Notes for 1.2.11 (RC)

This is the Release Candidate for GWT 1.2. Between this build and the subsequent GWT 1.2 official release, changes are limited to issues unique to GWT 1.2 RC.

See the GWT issue tracker for the complete list of enhancements and bug fixes in this release.

New Features

  • Full support for OS X developmentDevelop with GWT on OS X as easily as on Linux and Windows
  • Much faster hosted modeHosted mode startup time has improved significantly, but, even better, refreshes are now lightning fast — even when your source changes
  • **New HTTP request module **The HTTP functionality that GWT users have been asking for (custom headers, status code, timeouts, and more), all wrapped up in an API that’s easier to use than the JavaScript XMLHttpRequest object
  • **Widgets in TreeItems **Tree items can now contain arbitrary widgets…finally, you can easily create trees with checkboxes :-)

Release Notes for 1.1.10

Fixed Issues

  • Normalized behavior of GWT.getModuleBaseURL() with respect to hosted mode, web mode, RPC, and automatic resource injection ( post #1, post #2, post #3)
  • Clarified message in Grid class related to row/column out of bounds error (post)
  • i18nCreator fixed to work with Java 5.0 (post)
  • I18NSync (and therefore -i18n scripts) changed to replace dots with underscores when generating method names (post)
  • Additional character escaping in JSON strings (post)
  • Fixed bug calling toString() on nested JSON objects (post)
  • Fixed bug that caused the default font size of text in a FocusPanel to be zero post
  • Fixed TabPanel.insert() with asHTML argument (post)
  • Popups and DialogBoxes no longer underlap lists and combos in IE6 (post)
  • DialogBoxes can no longer be dragged beoynd the upper left corner of the browser window (post)
  • Buttons inside of FormPanels no longer automatically submit on Firefox; this is still a problem some versions of Safari and Opera (post)
  • TabPanel now sets the height of the internal DeckPanel to 100% to ensure all available space is used (post)
  • Fixed bug in Mozilla that was causing DialogBox.onKeyPressPreview() to see key as 0 (post)
  • DockPanel no longer lays out with a DeferredCommand; this makes it possible to correctly measure the size of PopupPanel (post)
  • SimplePanel is no longer abstract
  • Double click now fires correctly on IE6 (post)
  • Fixed RPC bug that caused deserialization errors or infinite loops with self-referential object graphs (post)
  • Fixed RPC bug that caused deserialization to fail on character arrays containing null characters (post)
  • Serializable classes whose superclass is serialized by a custom field serializer are now correctly deserialized on the server
  • Fixed bug related to FocusPanel that sometimes manifested during RPC async responses (post)
  • Fixed bug in JUnit assertEquals() for floating point values (delta was not honored correctly) (post)
  • Fixed internal compiler errors related to nested local subclasses, empty for loop expressions, and no-op unary plus operator. (post #1, post #2, post #3)
  • Fixed infinite loop in Integer.toHexString() (post)
  • Compiler now handling filesystem symbolic links in project structure (post)
  • Fixed rare JVM crash in Windows hosted mode related to JSNI function pointers

Release Notes for 1.1.0 (RC)

New Features

  • FileUpload widget The much-requested file upload widget
  • FormPanel widget Easily submit traditional HTML forms from GWT apps
  • RPC optimizations Client and server performance improvements and a more compact wire format
  • Automatic Resource Injection Modules can contain references to external JavaScript and CSS files, causing them to be automatically loaded when the module itself is loaded
  • Internationalization Easily localize strings and formatted messages
  • XML classes An XML library based on the W3C DOM
  • JSON classes JSON has moved into gwt-user.jar, and it’s much faster than the sample that shipped with 1.0.21
  • JUnit enhancements Unit tests are much, much faster than in 1.0.21, easier to configure, and you can now test asynchronous things like RPCs and timers
  • Javadoc Now included for your convenience, with sample code fragments
  • gwt-servlet.jar Although you should continue to build against gwt-user.jar as always, you only need to deploy gwt-servlet.jar with your webapps; it contains the subset of gwt-user.jar you’ll need to support RPC There are also a significant number of bug fixes from all the great feedback we’ve gotten from the developer forum. Please see the additional release notes for detailed information about other important changes in GWT since the previous release, including a few breaking API changes that we don’t want to catch you off guard.

Fixed Issues

See the appendix of fixed issues for the nitty-gritty list of things that we have fixed in this release, including smaller issues.

Behavioral Changes

Important changes in the behavior of existing GWT features.

Module Source and Public Paths

  • In previous versions of GWT, source and public path inclusions were based on physical directory structure; only files physically located with the module would be included. Going forward, source and public path inclusions are based on logical package structure. Once a package has been included, any files in that package become visible no matter where they are physically located.

JUnit Modules

  • GWT test modules (that is, modules intended to run GWTTestCase-derived JUnit test cases) no longer need to inherit the module. Additionally, it is no longer an error to declare entry points within a test module (they will be ignored when running under JUnit). Most test cases can now simply use the existing application module, which should simplify test case configuration.

Breaking API Changes

Based on user feedback, we’ve made a few API changes in this release that may require minor tweaks to your existing code when you upgrade. Any such changes that affect you should only take a few minutes to rectify.

  • We’ve moved add(), remove(), and clear() into this interface, so that any widget that can contain other widgets will be bound to this contract.
  • The add() method no longer returns a boolean. If a panel either cannot add a child widget without extra arguments, or cannot accept further widgets, it will throw an exception. This is in keeping with the fact that this is usually the result of an error in the code.
  • Its iterator is now required to support the remove() method.

  • Composites must now call initWidget() in their constructors, rather than setWidget(). This is more indicative of its actual purpose, and also serves to clear up any confusion with SimplePanel’s setWidget() method. Composite.setWidget() is now deprecated. and subclasses

  • We have added setWidget() to SimplePanel, which has more appropriate semantics for a panel that can contain only one child. The add() method is still present through the HasWidgets interface, but will fail if a widget is already present. This change is most likely to affect you if you use DialogBox or PopupPanel. To fix it, simply change your call to add() to setWidget() instead.

  • Cookies.getCookie() is now static, as it should have been from the beginning. There is no need to instantiate this class now.
  • You can now set cookies as well!

Appendix: Complete List of Fixed Issues

The list of issues below is a short synopsis of all of the major and minor issues fixed in this release. See the online GWT issues database for the important common issues.

  • String.matches(regex) should exist and doesn’t
  • Need a way to set individual List items selected/unselected (applies to multi-select listboxes)
  • DOM needs setBooleanAttribute, getBooleanAttribute.
  • HTMLTable.CellFormatter needs getStyleName() to match setStyleName().
  • FlexTable’s internal widget map does not correctly adjust for the user inserting rows and cells.
  • Window.getTitle/setTitle should be static

  • characters in filenames cause compilation to fail.

  • DynaTable has incorrect HTML
  • Change Timer API to use int not long
  • In hosted mode JSNI, marshall Java longs as VT_R8
  • Popups are not always positioned properly on Safari.
  • SWT source inclusion is wrong.
  • Safari crashes on exit under some circumstances.
  • TreeLogger throws away exception info in console mode.
  • Window needs a private ctor
  • Phone home version checking should actually compare ordering of version number
  • Hosted Mode server throws IllegalArgumentException when system is set to non-english locale
  • Trees have an unsightly 16-pixel left margin.
  • SimplePanel.remove() broken.
  • ScrollPanel doesn’t implement SourcesScrollEvents.
  • Make junit-web output to www dir
  • Add “hidden” feature to ArgHandler system.
  • JUnitShell could hang forever.
  • 1.5 VM fails to run junit because StackTraceElement 0-arg constructor disappeared.
  • Panel and ComplexPanel still have methods from old version of HasWidgets.
  • Nested tables can fire events from the wrong one.
  • Make sure JSNI refs to functions can be passed around and used as real function pointers.
  • AbsolutePanel doesn’t position its children consistently.
  • JSONParser does not handle generic JSONValues in the encoded json string correctly; always assumes its a JSONObject
  • Remove -notHeadless from GWTShell (only applies to GWTUnitTestShell)
  • Number of results returned from split() differs in Java/JavaScript (see description)
  • Helper scripts don’t work for base package.
  • Grid fails to update row count when removing.
  • JSONString, toString does not enclose its characters in double quotes
  • Selection issue when removing widgets from TabPanel.
  • JSONParser always assumes root type is JSONObject
  • ClassSourceFileComposer should not handle Class objects.
  • Modules cannot supercede files from inherited modules
  • Simple & ComplexPanel shouldn’t implement getChildCount(), getChild(), etc.
  • Negative byte values passed into JavaScript become positive
  • The rpc servlet needs a thread-local HttpServletResponse to match the thread-local request.
  • Appending char to a String behaves incorrectly.
  • Remove STL dependency from gwt-ll
  • Using xhtml doctype causes popups to be misplaced on Mozilla browsers.
  • JsniInjector fails to match lines when there are Javadoc comments.
  • Add whitelist bypass for hosted browser
  • PopupPanel example is wrong.
  • UIObject needs a title property.
  • JSNI methods in local classes don’t work in hosted mode.
  • HashMap throws a JavaScript error under some circumstances.
  • Source and Public module tags should be logical instead of physical.
  • Document that module source and public tags are now logical rather than physical.
  • Default .launch file fails to use project’s full classpath.

  • RemoteServiceServlet sends back HTTP 200 OK but no content under WebSphere.
  • Widget.onLoad() is called too early sometimes.
  • Is it really a good idea to have add(Widget) on Panel?
  • Web-mode JUnit that reports via RPC
  • Tree fires onTreeItemStateChanged twice.
  • Make JSON APIs part of gwt-user.jar
  • Async JUnit
  • String.equalsIgnoreCase(null) throws exception in web mode
  • Using a class literal for a pruned typed causes ICE
  • Make all built-in implementations of HasWidgets.iterator() support remove().
  • JSON is slow in Web mode
  • StringBuffer uses string concatenation, and is n-squared as a result
  • Identical Strings can compare false in web mode.
  • Tweaks to the property provider environment to support locale and improve code uniformity b/w hosted and web mode
  • Server-side serialization is unusably slow for large data sets

  • Client side serialization is unusably slow for large datasets
  • Format source for JUnitTestCaseStubGeneratorm, ServerSerializationStream
  • MethodDispatch not working correctly on IE.
  • JavaScriptObject rescuing is incomplete.
  • Reduce RPC wire size by not quoting non-strings.
  • Cyclic object graphs can be corrupted during deserialization on the server
  • Test methods that throw checked exceptions cause the generated code to fail to compile
  • Allow RemoteServiceResponse compression to be controlled by subclasses
  • Startup timing bug makes RootPanel.get(id) throw an NPE
  • Change whitelist/blacklist settings to be command-line switches rather than system properties
  • KeyCode is always 0 for keypress events on Mozilla.
  • Add Panel.remove(int) convenience method.
  • File Upload Widget
  • PopupPanel needs to deal better with being empty.
  • CheckBox.setEnabled() has reversed sense.
  • History tokens have problems with URL encoding.
  • Loosen restriction on when DockPanel.CENTER child may be added.
  • AbsolutePanel needs getWidgetLeft() and getWidgetTop().
  • Decision: how should FlowPanel behave?
  • Samples with composites need to call initWidget() instead of the deprecated setWidget().
  • RootPanel.get(String) should not be clearing the div’s contents.
  • ListBox, Image, and Hyperlink are missing style names, despite doc
  • Hyperlink.removeClickListener is broken.
  • Don’t allow tabs to word-wrap internally on TabPanel
  • Turkish locale problem with the RPC generated code - probably affects others too
  • StackPanel.add() totally screwy.
  • Referencing a field that could cause static initialization fails to cause a side effect.

Release Notes for 1.0.21

Fixed Issues