JRE / JDK under Debian

Debian provides many Java implementation. Each of them have a development environment (JDK) and a runtime (known as JRE, or Java Virtual Machines JVM).

Here's a list of Java environment. (Run aptitude search "?provides(java-runtime)" on your system to list available packages).

Origin	Spec.	Packages	Plugin	Free	Comments
GNU's GIJ/GCJ 4.2, 4.3	v5	JRE:gij (java-gcj-compat...) JDK:gcj	yes		Installed by default.
Sun Java 1.5	v5	JRE:sun-java5-jre JDK:sun-java5-jdk	yes		Sun's JVM ! Compatible with older Java programs Available on i386 and amd64 only.
Sun Java 1.6	v6	JRE:sun-java6-jre JDK:sun-java6-jdk	yes		Sun's JVM ! Latest release Available on i386 and amd64 only.
OpenJDK	v6	JRE:openjdk-6-jre JDK:openjdk-6-jdk	compatible: icedtea-gcjwebplugin or icedtea6-plugin		A GPL2 version of Sun's JDK ! Available on all archs.
Kaffe	v1?	JRE:kaffe JDK:kaffe	no		Kaffe, another JVM

Other JRE/JDK: It is possible to package and install other JRE/JDK from (Blackdown, IBM, Sun) using JavaPackage:

BlackDownJava, easy installation and with Mozilla plugin. (No longer developed)
IBMJava
Sun

The following JRE/JDK aren't available in Debian anymore (as of DebianLenny) :

sablevm
Sun's JRE <1.5

Understanding Java Virtual packages names

There are several virtual packages used in Debian for Java. These cover runtime compatibility and come in two flavours; headless (omits graphical interfaces) and normal. A dependency on javaX-runtime means that the package can work with any runtime which implements version X. Runtimes should provide all virtual packages which they support, so openjdk 6 provides java2-runtime, java5-runtime and java6-runtime.

java1-runtime, java2-runtime, java5-runtime, java6-runtime
java1-runtime-headless, java2-runtime-headless, java5-runtime-headless, java6-runtime-headless

Switching

Most java-related executables, multiple of which can be installed at any time, are managed by the 'alternatives' system. Instead of managing each alternative separately, you can update them all in one go with 'update-java-alternatives' from java-common

Developers - Java packaging work in Debian

general information and coordination

Java/Packaging - Tools for packaging Java apps and libraries in Debian
Java/RoadMap
Java/ChangeLog - Java/ChangeLog/Etch
Packaging Community
- Debian Java Packaging Project @ Alioth
- Debian Java List
- Teams/JavaPackaging pre-unstable/experimental repository
Java/DevJam -> Developer Java Meeting
Java/ResolveJavaNaming - Java Trademark Issues.
CommonJavaPackaging - Coordination not to reinvent the wheel...
Java/JavaSvn - how to use SVN to package Java stuff

Work on specific application packages

Java/MoveToMain packages to be moved to main
Java/AlreadyMovedToMain - packages cotained in main
- Java/OpenJDKPackaging - things going on in packaging an openjdk for debian
Java/RequestedPackages - Apps people want to see packaged and which are in the process of being packaged.
http://www.debian.org/devel/wnpp/requested
http://www.debian.org/devel/wnpp/being_packaged
Netbeans uploaded to NEW according to ITP: netbeans -- An IDE for Java

TODO(wiki consolidation): maybe everything should be moved from here to Java/RequestedPackages?

User Documentation

Using Java in Debian

To install the default JRE on your system, run :

apt-get install default-jre

Debian Java FAQ outside of this wiki
JavaFAQ - in this wiki, only one question so far
Eclipse
Building Java apps/libs on Debian (... with free tools): Java/Building/JOnAS
Java in the Webbrowser:
- Mozilla (Java section).
- TestJava