The GCJ Frequently Asked Questions (FAQ)

  1. General Questions

  2. Java Feature Support

  3. Build Issues

  4. GCJ Compile/Link Questions

  5. Runtime Questions

  6. Programming Issues

<<Anchor(gen)>>General Questions

<<Anchor(gen_lic)>>What license is used for libgcj?

<<Anchor(gen_contr)>>How can I contribute to libgcj?

<<Anchor(gen_work)>>Will GCJ and libgcj work on my machine?

<<Anchor(gen_dbg)>>How can I debug my Java program?

<<Anchor(gen_nat)>>Can I interface byte-compiled and native java code?

    $ gcj -shared -o
    $ gij HelloWorld

<<Anchor(feat)>>Java Feature Support

<<Anchor(feat_api)>>What Java API's are supported? How complete is the support?

<<Anchor(feat_nat)>>Does GCJ support using straight C native methods''a la''JNI?

<<Anchor(feat_cni)>>Why does GCJ use CNI?

<<Anchor(feat_awt)>>What is the state of AWT support?

<<Anchor(feat_swing)>>How about support for Swing?

<<Anchor(feat_rmi)>>What support is there for RMI?

<<Anchor(feat_oss)>>Can I use any code from other free software projects to supplement libgcj's current features?

<<Anchor(feat_lang)>>What features of the Java language are/aren't supported?

<<Anchor(bld)>>Build Issues

<<Anchor(bld_bld)>>I need something more recent than the last release. How should I build it?

<<Anchor(bld_sol)>>Linker bug on Solaris

    ld: warning: option -o appears more than once, first setting taken
    ld: fatal: file cannot open file: No such file or directory
    ld: fatal: File processing errors. No output written to .libs/
    collect2: ld returned 1 exit status

<<Anchor(bld_cfgsrc)>>Can I configure/build in the source tree?

    $ ./configure [...]
    Configuring for a i686-pc-linux-gnu host.
    *** Cannot currently configure in source tree.

    $ mkdir build
    $ cd build
    $ ../configure [...]

<<Anchor(bld_sig)>>My libgcj build fails with "invalid use of undefined type struct sigcontext_struct".

<<Anchor(bld_import)>>How do I import a current GNU Classpath source tree?

<<Anchor(comp_undef)>>Why do I get {{{undefined reference to `main'}}} errors?

<<Anchor(comp_src)>>Can GCJ only handle source code?

<<Anchor(comp_oth)>>"gcj -C" Doesn't seem to work like javac/jikes. Whats going on?

<<Anchor(comp_search)>>Where does GCJ look for files?

<<Anchor(comp_res)>>How does GCJ resolve whether to compile .class or .java files?

<<Anchor(comp_dso)>>I'm getting 'undefined symbol: __dso_handle'.

<<Anchor(run)>>Runtime Questions

<<Anchor(run_core)>>My program is dumping core! What's going on?

<<Anchor(run_gcsegv)>>When I run the debugger I get a SEGV in the GC! What's going on?

<<Anchor(run_faster)>>I have just compiled and benchmarked my Java application and it seems to be running slower than than XXX JIT JVM. Is there anything I can do to make it go faster?

<<Anchor(run_profgc)>>Can I profile Garbage Collection?

<<Anchor(run_heap)>>How do I increase the runtime's initial and maximum heap sizes?

<<Anchor(run_prof)>>How can I profile my application?

<<Anchor(run_hang)>>My program seems to hang and doesn't produce any output.

<<Anchor(prog)>>Programming Issues

<<Anchor(prog_cni)>>Are there any examples of how to use CNI?

<<Anchor(prog_cpp)>>Is it possible to invoke GCJ compiled Java code from a C++ application?

None: GCJ_FAQ (last edited 2008-09-08 18:17:06 by GeraldPfeifer)