Contributing to the GCJ Project

The main GCC contribute page contains general information; below you will find GCJ-specific details.

Project Ideas

We've started maintaining a list of useful projects.

Coding Standards

We follow the GCC Coding Conventions with some extrapolations concerning Java programming style:

  • Open braces go on a new line (like GNU C style).
  • Two space indent for methods and inner classes
  • if, for, try, and synchronized blocks are indented four spaces (two for the braces, and an additional two for the code).
  • The open brace for a method body is indented only as far as the method header.

Submitting Patches

Send libgcj patches to This list is archived.

Patches to the GCJ front end — the gcc/java directory — should be sent to the gcc-patches list.


We're accepting test case patches.

  • Put the .java file in libjava/testsuite/libjava.compile (if it is an expected compiler failure or other compile-time test -- run-time tests usually go in libjava.lang)
  • If the file is "" make a "foo.xfail" file. For an expected failure the only thing in there should be "shouldfail"
  • If the test case matches a Java PR, it is customary to name it after the PR number.
  • Send the patch to java-patches and then commit of you're allowed to.

More detailed documentation on how to run tests is included in the GCC installation notes.