GNU Compiler for Java

The GNU compiler for the Java Programming Language ( GCJ ) is an Ahead -of- time compiler for the Java programming language and part of the GNU Compiler Collection. GCJ is both a byte code as well as a binary code compiler. He can Java source code to Java bytecode to native machine code Java-Byte/Quellcode and all Java Archive (JAR) for various processor architectures compile.

GCJ is not used while the class libraries from Sun, but the free Java implementation of GNU Classpath. Since this class library is not yet fully implemented, it can cause problems with some Java programs.