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13. Java and java-gcj-compat

This release of Fedora Core includes a free and open source Java environment called java-gcj-compat. The java-gcj-compat collection includes a tool suite and execution environment that is capable of building and running many useful programs that are written in the Java programming language.

Fedora Core Does Not Include Java

Java is a trademark of Sun Microsystems. java-gcj-compat is an entirely free software stack that is not Java, but may run Java software.
The java-gcj-compat infrastructure has three key components: a GNU Java runtime (libgcj), the Eclipse Java compiler (ecj), and a set of wrappers and links (java-gcj-compat) that present the runtime and compiler to the user in a manner similar to other Java environments.
The Java software packages in this Fedora release use the java-gcj-compat environment. These packages include Base, Eclipse, and Apache Tomcat. Refer to the Java FAQ at for more information on the java-gcj-compat free Java environment in Fedora.

Include Location and Version Information in Bug Reports

When making a bug report, be sure to include the output from these commands:
which java && java -version && which javac && javac -version

13.1. Handling Java and Java-like Packages

In addition to the java-gcj-compat free software stack, Fedora Core lets you install multiple Java implementations and switch between them using the alternatives command line tool. However, every Java system you install must be packaged using the JPackage Project packaging guidelines to take advantage of alternatives. Once these packages are installed properly, the root user may switch between java and javac implementations using the alternatives command:
alternatives --config java  
alternatives --config javac