While writing gcj and libgcj we have, of course, relied
heavily on documentation from Sun Microsystems. In particular we have
used The Java Language Specification (both first and second editions),
the Java Class Libraries (volumes one and two), and the Java Virtual
Machine Specification. In addition we've used the online documentation
at http://java.sun.com/.
The current gcj home page is http://gcc.gnu.org/java/.
For more information on gcc, see http://gcc.gnu.org/.
Some libgcj testing is done using the Mauve test suite. This is
a free software Java class library test suite which is being written
because the JCK is not free. See
http://sources.redhat.com/mauve/ for more information.