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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.
|
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 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.
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
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
The 64-bit JNI libraries shipped by default on x86_64 systems in Fedora Core and Extras do not run on 32-bit JREs. Either switch to a 64-bit Java alternative, or install the 32-bit version of the packages, if available. To install a 32-bit version, use the following command:
yum install <package_name>.i386
Likewise, the 32-bit JNI libraries shipped by default on ppc64 systems do not run with a 64-bit JRE. To install the 64-bit version, use the following command:
yum install <package_name>.ppc64
This release of Fedora Core includes a preview release of
gcjwebplugin
, a
Firefox plugin for Java applets.
gcjwebplugin
is not enabled by default.
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-4.1.1/README.libgcjwebplugin.so
,
as installed by the gcc rpm. The README
explains how to enable the plugin and the risks associated with
doing so.
Fedora Core 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.
Mixing Packages from Fedora and JPackage | |
---|---|
Research package compatibility before you install software from both the Fedora and JPackage repositories on the same system. Incompatible packages may cause complex issues. |
This release of Fedora Core includes Fedora Eclipse, which is based on the Eclipse SDK version 3.2. The "New and Noteworthy" page for this release can be accessed here.
Released in June 2006, the SDK is known variously as "the Eclipse Platform," "the Eclipse IDE," and "Eclipse." The Eclipse SDK is the foundation for the combined release of ten Eclipse projects under the Callisto combined release umbrella. A few of these Callisto projects are included in Fedora Core and Extras: CDT, for C/C++ development, and GEF, the Graphical Editing Framework.
We hope to augment these projects with others as this Fedora cycle goes on. Likely candidates for inclusion include EMF, the Eclipse Modeling Framework, and VE, the Visual Editor. As of this writing, it is expected that an updated version of PyDev, the Python development tools, is going to be available in Fedora Extras. Assistance in getting these projects packaged and tested with GCJ is always welcome. Contact the interested parties through fedora-devel-java-list and/or #fedora-java on freenode.
Fedora also includes plugins and features that are particularly
useful to FOSS hackers: ChangeLog
editing with eclipse-changelog
and
Bugzilla interaction with
eclipse-bugzilla
. Our CDT package also
includes work-in-progress support for the GNU Autotools. The
latest information regarding these projects can be found at the
Fedora Eclipse
Project page.
Fedora Eclipse contains a patch to allow non-root users to make
use of the Update Manager functionality for installing
non-packaged plugins and features. Such plugins are installed in
the user's home directory under the .eclipse
directory. Please note,
however, that these plugins do not have associated GCJ-compiled
bits and may therefore run slower than expected.