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7.2. Java

7.2.1. Best of breed free software Java implementation

Fedora includes multiple best of breed free software Java(TM) implementations, obtained through active adoption of innovative technology integrations produced by Fedora and others within upstream projects. The implementations integrated into Fedora are based on OpenJDK ( and the IcedTea GNU/Linux distribution integration project (, or based on alternatives such as the GNU Compiler for Java (GCJ - and the GNU Classpath core class libraries ( All Fedora innovations are pushed upstream to get the widest possible integration of the technologies in general Java implementations.
The implementation of OpenJDK 6 included in Fedora 10 uses the HotSpot virtual machine runtime compiler on x86, x86_64, and SPARC. On PowerPC (PPC) it uses the zero interpreter, which is slower. On all architectures an alternative implementation based on GCJ and GNU Classpath is included that includes an ahead-of-time compiler to produce native binaries.
Fedora binaries for selected architectures (currently only x86 and x86_64 based on OpenJDK) are tested against the Java Compatibility Kit (JCK) by Red Hat to guarantee 100% compatibility with the Java Specification (JDK 1.6 at this time).