This document is about configuring Gerrit Code Review into an Eclipse workspace for development and debugging with GWT.

Java 6 or later SDK is also required to run GWT’s compiler and runtime debugging environment.

Project Setup

In your Eclipse installation’s eclipse.ini file, add the following line in the vmargs section:


Without this setting, annotation processing does not work reliably and the build is likely to fail with errors like:

  Could not write generated class ... javax.annotation.processing.FilerException: Source file already created


  AutoAnnotation_Commands_named cannot be resolved to a type

In Eclipse, choose 'Import existing project' and select the gerrit project from the current working directory.

Expand the gerrit project, right-click on the buck-out folder, select 'Properties', and then under 'Attributes' check 'Derived'.

Note that if you make any changes in the project configuration that get saved to the .project file, for example adding Resource Filters on a folder, they will be overwritten the next time you run tools/eclipse/

Code Formatter Settings

Import tools/GoogleFormat.xml using Window → Preferences → Java → Code Style → Formatter → Import…​

This will define the 'Google Format' profile, which the project settings prefer when formatting source code.

Site Initialization

Build once on the command line with Buck and then follow Site Initialization in the Developer Setup guide to configure a local site for testing.


Running the Daemon

Duplicate the existing launch configuration:

  • In Eclipse select Run → Debug Configurations …​

  • Java Application → gerrit_daemon

  • Right click, Duplicate

  • Modify the name to be unique.

  • Switch to Arguments tab.

  • Edit the -d program argument flag to match the path used during 'init'. The template launch configuration resolves to ../gerrit_testsite since that is what the documentation recommends.

  • Switch to Common tab.

  • Change Save as to be Local file.

  • Close the Debug Configurations dialog and save the changes when prompted.

Running GWT Debug Mode

The gerrit_gwt_debug launch configuration uses GWT’s Super Dev Mode.

  • Make a local copy of the gerrit_gwt_debug configuration, using the process described for gerrit_daemon above.

  • Launch the local copy of gerrit_gwt_debug from the Eclipse debug menu.

  • If debugging GWT for the first time:

    • Open the codeserver URL and add the Dev Mode On and Dev Mode Off bookmarklet to your bookmark bar.

    • Activate the source maps feature in your browser. Refer to the Chrome and Firefox developer documentation.

  • Load the Gerrit page.

  • Open the source tab in developer tools.

  • Click the Dev Mode On bookmark to incrementally recompile changed files.

  • Select the gerrit_ui module to compile (the Compile button can also be used as a bookmarklet).

  • In the developer tools source tab, open a file and set a breakpoint.

  • Navigate to the UI and confirm that the breakpoint is hit.

  • To end the debugging session, click the Dev Mode Off bookmark.

After changing the client side code:
  • Hitting F5 in the browser only reloads the last compile output, without recompiling.

  • To reflect your changes in the debug session, click Dev Mode On then Compile.

Running GWT Debug Mode for Gerrit plugins

A Gerrit plugin can expose GWT module and its implementation can be inspected in the SDM debug session.

codeserver needs two additional inputs to expose the plugin module in the SDM debug session: the module name and the source folder location. For example the module name and source folder of cookbook-plugin should be added in the local copy of the gerrit_gwt_debug configuration:

  com.googlesource.gerrit.plugins.cookbook.HelloForm \
  -src ${resource_loc:/gerrit}/plugins/cookbook-plugin/src/main/java \
  -- --console-log [...]

After doing that, both the Gerrit core and plugin GWT modules can be activated during SDM (debug session)[].