GWT Open Source Project

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  1. bfa96cd Pin synthesizd closure constructor to initial fragment by Ray Cromwell · 12 days ago master
  2. 720d817 Place class literal in a correct fragment for -XenableClosureFormat. by Roberto Lublinerman · 2 weeks ago
  3. fa1a1bf Handle NaN and -0.0 in Math.signum by Andrei Korzhevskii · 12 days ago
  4. dc2e7f6 marking custom serialization methods with GwtIncompatible by Manuel Carrasco Moñino · 2 weeks ago
  5. cd8e225 Sync back changes to dev/BUILD. by Roberto Lublinerman · 2 weeks ago


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GWT is the official open source project for GWT releases 2.5 and onwards.

In this document you have some quick instructions to build the SDK from source code and to run its tests.

For a more detailed documentation visit our web site. If you are interested in contributing with the project, please read the Making GWT better section.

Building the GWT SDK:

  • In order to build GWT, java and ant are required in your system.

  • Optional: if you want to compile elemental you need python and g++ installed.

  • You need the GWT tools repository checked out and up-to-date. By default it is expected to be found at ../tools. You can override the default location using the GWT_TOOLS environment variable or passing argument to ant.

  • To create the SDK distribution files run:

$ ant clean elemental dist-dev

or if you don’t have python and g++ just run

$ ant clean dist-dev

Then you will get all .jar files in the folder build/lib and the redistributable file will be: build/dist/

if you want to specify a different version number run:

$ ant elemental clean dist-dev -Dgwt.version=x.x.x

  • To compile everything including examples you have to run

$ ant clean elemental dist

How to verify GWT code conventions:

  • In GWT we have some conventions so as all code written by contributors look similar being easier to review.

  • After you make any modification, run this command to compile everything including tests, to check APIs, and to verify code style. It shouldn’t take longer than 3-4 minutes.

$ ant compile.tests apicheck checkstyle -Dprecompile.disable=true

How to run GWT tests

  • Previously to run any test you have to set some environment variables to guarantee that they are run in the same conditions for all developers.

In a Unix like platform you can use the export command:

$ export TZ=America/Los_Angeles ANT_OPTS=-Dfile.encoding=UTF-8

But in Windows™ you have to set the time-zone in your control panel, and the environment variables using the command set.

  • Finally you can run all test suites with the following command, but be prepared because it could take hours, and probably it would fail because of timeouts, etc.

$ ant test

  • Thus, you might want to run only certain tests so as you can focus on checking the modifications you are working on.

GWT build scripts use specific ant tasks and a bunch of system properties listed in the following table to specify which tests to run and how.

For instance to run the task test in the module user you have to change to the user folder and run ant with the task as argument, adding any other property with the -D flag:

$ ( cd user && ant test -Dtest.emma.htmlunit.disable=true ; cd .. )

Module         | Task                   | Property to skip               | Description
-------------- | ---------------------- | ------------------------------ | ----------------------
dev            | test                   |               | GWT compiler & dev libraries
codeserver     | test                   | test.codeserver.disable        | SuperDevMode server
user           | test                   | test.user.disable              | GWT user API and JRE emulation
user           | test.nongwt            | test.nongwt.disable            | Run tests that not require GWTTestCase
user           |      |      | Run dev-mode tests with HtmlUnit
user           | test.web.htmlunit      | test.web.htmlunit.disable      | Run web-mode tests with HtmlUnit
user           | test.draft.htmlunit    | test.draft.htmlunit.disable    | Run draft compiled HtmlUnit tests
user           | test.nometa.htmlunit   | test.nometa.htmlunit.disable   | Run -XdisableClassMetadata tests with HtmlUnit
user           | test.emma.htmlunit     | test.emma.htmlunit.disable     | Run emma tests with HtmlUnit
user           | test.coverage.htmlunit | test.coverage.htmlunit.disable | Run tests for coverage support
user           |      |      | Run dev-mode tests using Selenium RC servers
user           | test.web.selenium      | test.web.selenium.disable      | Run web tests using Selenium RC servers
user           | test.draft.selenium    | test.draft.selenium.disable    | Run draft compiled tests using Selenium RC servers
user           | test.nometa.selenium   | test.nometa.selenium.disable   | Run -XdisableClassMetadata tests using Selenium RC servers
user           | test.emma.selenium     | test.emma.selenium.disable     | Run emma tests with Selenium RC servers
requestfactory | test                   | test.requestfactory.disable    | Request Factory library
elemental      | test                   | test.elemental.disable         | Elemental library
elemental      | test.nongwt            | test.nongwt.disable            | Run elemental tests that not require GWTTestCase
elemental      |      |      | Run elemental dev-mode tests with HtmlUnit
elemental      | test.web.htmlunit      | test.web.htmlunit.disable      | Run elemental web-mode tests with HtmlUnit
tools          | test                   |             | Some tools used in GWT development

Additionally you can utilize some variables to filter which test to run in each task:

Module         | Task                                  | Properties                           | Default
dev/core       | test                                  | | `**/com/google/**/*Test.class`
               |                                       | |
user           | test                                  | gwt.junit.testcase.includes          | `**/*Suite.class`
user           | test.nongwt                           | gwt.nongwt.testcase.includes         | `**/*JreSuite.class`
               |                                       | gwt.nongwt.testcase.excludes         |
user           | test.web.* test.draft.* test.nometa.* | gwt.junit.testcase.web.includes      | `**/*Suite.class`
               |                                       | gwt.junit.testcase.web.excludes      | `**/*JsInteropSuite.class,**/*JreSuite.class,***/OptimizedOnly*`
user           |* test.emma.*                |      | `**/*Suite.class`
               |                                       |      | `**/*JsInteropSuite.class,**/*JreSuite.class,***/OptimizedOnly*`


  • Run all tests in dev

$ ( cd dev && ant test ; cd .. )

_Note: that the last `cd ..' is only needed in Windows._
  • There is another option to do the same but without changing to the module folder. We have to specify the module as the ant task, and the task as a target argument.

$ ant dev -Dtarget=test

  • Run all tests in codeserver

$ ( cd dev/codeserver && ant test )


$ ant codeserver -Dtarget=test

_Note: that we disable dev tests because code server depends on dev
and we don`t want to run its tests._
  • Run all tests in elemental:

$ ( cd elemental && ant test.nongwt )


$ ant elemental -Dtarget=test -Dtest.user.disable=true

_Note: that we have to disable dev and user tests because elemental
depends on both._
  • Run all tests in tools

$ ant tools -Dtarget=test -Dtest.user.disable=true

  • Run only the JsniRefTest in dev

$ ant dev -Dtarget=test \"**/JsniRefTest.class"

  • Run a couple of tests in dev

$ ant dev -Dtarget=test \"**/JsniRefTest.class,**/JsParserTest.class"

Note: that you have to use regular expressions separated by comma to select the test classes to execute.

  • Run all Jre tests in user, they should take not longer than 3min. We have two ways to run them. Although the second case is more complex it is here to know how disable properties work.

$ ( cd user && ant test.nongwt )


$ ant user -Dtarget=test \ -Dtest.codeserver.disable=true \ -Dtest.requestfactory.disable=true \ -Dtest.elemental.disable=true \ \ \ -Dtest.web.htmlunit.disable=true \ -Dtest.coverage.htmlunit.disable=true \ \ -Dtest.draft.htmlunit.disable=true \ -Dtest.draft.selenium.disable=true \ -Dtest.emma.htmlunit.disable=true \ -Dtest.emma.selenium.disable=true \ -Dtest.nometa.htmlunit.disable=true \ -Dtest.nometa.selenium.disable=true \ -Dtest.web.selenium.disable=true

_Note: that we have to set all disable variables but `test.nongwt.disable`_
  • Run certain Jre tests in the user module.

$ ( cd user && ant test.nongwt -Dgwt.nongwt.testcase.includes="**/I18NJreSuite.class" )

  • Run all GWT tests in user using htmlunit in dev mode.

$ ( cd user && ant )