GCJ: The GNU Compiler for Java

GCJ is a portable, optimizing, ahead-of-time compiler for the Java -Programming Language. It can compile Java source code to Java bytecode -(class files) or directly to native machine code, and Java bytecode to -native machine code.

Compiled applications are linked with the GCJ runtime, -libgcj, which provides the core class libraries, a -garbage collector, and a bytecode interpreter. libgcj can -dynamically load and interpret class files, resulting in mixed -compiled/interpreted applications. -It has been merged with GNU Classpath and -supports most of the 1.4 libraries plus some 1.5 additions. -

-GCJ can also be configured as a cross-compiler, suitable for embedded -systems programming. Recent versions of the GNU Debugger support GCJ -(short tutorial). -

GCJ News

- - - -

September 22, 2009: GCJ support on Windows (Cygwin and MinGW) targets has been enhanced -with a number of bugfixes, and the option to build libgcj in DLL form -for dynamic runtime linking.
March 30, 2007: Keith Seitz and Kyle Galloway have made considerable progress on -GCJ's implementation of the JDWP. It is now possible to use eclipse -to debug interpreted Java code using libgcj as the VM.
February 20, 2007: Jakub Jelinek checked in a patch to make -java.util.TimeZone read system timezone files. Now -libgcj does not require updating when a timezone change is published.
February 15, 2007: David Daney and Johannes Schmidt of Avtrex checked in a new -gc-analyze tool. This is a valuable debugging tool which -can be used to analyze heap dumps from libgcj.
January 8, 2007: We've merged the gcj-eclipse branch to svn trunk. -The merge changes gcj to use the Eclipse compiler as a front end, -enabling all 1.5 language features. This merge also brings in a new, -generics-enabled version of Classpath, including some new tools. This -new code will appear in GCC 4.3.
September 11, 2006: Joel Dice has -announced micro-libgcj -0.1, a lightweight version of libgcj intended to provide a usable -subset of Java's features while remaining small and self-contained. -This release fixes compatibility issues present in the initial 0.0 -release and adds -optional SWT -support.
June 13, 2006: The May 2006 issue of Linux Journal contains the article "Embedded Java with -GCJ" by Gene Sally.
June 6, 2006: RMS approved the plan to use the Eclipse compiler as the new gcj -front end. Work is being done on the gcj-eclipse branch; -it can already build libgcj. This project will allow us to ship a 1.5 -compiler in the relatively near future. The old gcjx -branch and project is now dead.
May 20, 2006: John David Anglin and Andreas Tobler checked in a patch -to enable libjava to be built by default on the HP-UX PA 32-bit platform. -
May 19, 2006: Mark Wielaard has imported GNU Classpath 0.91 (release -notes) into GCJ.
April 26, 2006: Andrew Haley has merged in a patch -that eliminates conservative scanning of static data and considerably speeds -up garbage collection in many cases (for example, halving the time spent in -garbage collection when running Eclipse). -
April 17, 2006: Tom Tromey has announced the -availability of two experimental Just-In-Time (JIT) interpreters for GCJ based -on libjit and LLVM respectively. The source code for these -JITs is available via the "gcj-jit" module of the rhug repository. -
April 4, 2006: fastjar has been removed from the GCC source tree and made into -a separate project. -The GCJ build process now requires an external tool for creating JARs - it -searches for a tool named either jar or fastjar -during configuration and reports an error if it is unable to find such a tool. -
March 15, 2006: David Daney has merged in a patch that -adds the new -freduced-reflection option to GCJ. This option -prevents GCJ from generating most of the reflection metadata for classes -resulting in smaller binaries. There are some caveats to using this option -though - please read the GCJ manual for the implications of using this option. -
March 9, 2006: Mark Wielaard has imported GNU Classpath 0.90 (release -notes) into GCJ.
February 8, 2006: Mark Wielaard has written "A -look at GCJ 4.1" for LWN.net.

- -

Less recent GCJ news

- -

The GNU Compiler for the JavaTM Programming Language

GCJ News

The GNU Compiler for the Java^TM Programming Language