![[Tip]](./stylesheet-images/tip.png) | Latest Release Notes on the Web |
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These release notes may be updated. Visit http://docs.fedoraproject.org/release-notes/ to view the latest release notes for Fedora. |
This release of Fedora 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.
![[Note]](./stylesheet-images/note.png) | Fedora Does Not Include Java |
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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 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 OpenOffice.org Base, Eclipse, and Apache Tomcat. Refer to the Java FAQ at http://www.fedoraproject.org/wiki/JavaFAQ for more information on the java-gcj-compat free Java environment in Fedora.
![[Important]](./stylesheet-images/important.png) | Include Location and Version Information in Bug Reports |
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When making a bug report, be sure to include the output from these commands: which java && java -version && which javac && javac -version |
In addition to the java-gcj-compat free
software stack, Fedora 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
This release of Fedora includes a preview release of
gcjwebplugin, a Firefox plugin for Java applets.
gcjwebplugin is not enabled by default because although
the security implementation in GNU Classpath is being actively developed,
it is not mature enough to run untrusted applets safely. That said, the
AWT and Swing implementations in GNU Classpath are now sufficiently mature
that they can run many applets deployed on the web. Adventurous users who
want to try gcjwebplugin can read
/usr/share/doc/libgcj-4.1.2/README.libgcjwebplugin.so,
as installed by the libgcj package. The
README explains how to enable the plugin and the
risks associated with doing so.
Fedora includes many packages derived from the JPackage Project, which provides a Java software repository. These packages are modified in Fedora to remove proprietary software dependencies and to make use of GCJ's ahead-of-time compilation feature. Use the Fedora repositories to update these packages, or use the JPackage repository for packages not provided by Fedora. Refer to the JPackage website at http://jpackage.org for more information on the project and the software it provides.
![[Warning]](./stylesheet-images/warning.png) | Mixing Packages from Fedora and JPackage |
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Research package compatibility before you install software from both the Fedora and JPackage repositories on the same system. Incompatible packages may cause complex issues. |
Refer to the latest release notes pertaining to Eclipse at http://fedoraproject.org/wiki/Docs/Beats/Devel/Tools/Eclipse.
This release of Fedora includes maven2, a Java
project management and project comprehension tool. Maven can be
invoked by the mvn and mvn-jpp commands.
The former makes Maven behave just like upstream Maven, while the
latter calls mvn with additional properties that make
off-line building easier.
The maven2 package in Fedora is modified to work in a
fully off-line mode. With no additional properties defined (the
mvn command), maven2 works exactly like
upstream Maven. Users may define additional properties to
facilitate off-line builds, or call mvn-jpp, a
wrapper that defines the most commonly used properties for
off-line building. The properties and their usage details are
described in the
/usr/share/doc/maven2-2.0.4/maven2-jpp-readme.html
file, which comes from the maven2-manual package.