As of JavaOne 2008, Ubuntu 8.04LTS (Hardy Heron) includes a 100% Free software implementation based on the OpenJDK source code. The Ubuntu implementation is in the Ubuntu Universe repository.

mepcotterell: I can build all Java5 and Java6 Eclipse components with eclipse-sourceBuild-srcFetch-3.4.zip and OpenJDK on hardy. However, we need a suitable 1.4 JDK present to build the Java1.4 Eclipse components that are being misinterpreted by the compiler as being Java5+ generics.

To compile Eclipse:

1) Install the OpenJDK: sudo aptitude install openjdk-6-jdk
2) Get eclipse-sourceBuild-srcFetch-3.4.zip: http://download.eclipse.org/eclipse/downloads/drops/R-3.4-200806172000/download.php?dropFile=eclipse-sourceBuild-srcFetch-3.4.zip
3) Extract eclipse-sourceBuild-srcFetch-3.4.zip
4) Modify buildScripts/build.properties

You can figure out your bootclasspath files by typing: find /usr/lib/jvm/java-6-openjdk/jre/lib/ | grep .jar

Set the value of each property (J2SE-1.4, J2SE-5, and J2SE-6) to a colon separated list of the jar files found above.

** We really need to use Java 1.4 jars for J2SE-1.4 because this is where the problem is.

** I tried installing java1-runtime (sudo aptitude install java1-runtime) and then using the files found using (find /usr/share/java/ | grep .jar
) for the J2SE-1.4 property. The result is still a failed build.

5) In the buildScripts directory, run: ./build -os linux -ws gtk -arch $(uname -m)
6) Wait.
7) Wait some more.
8) Notice that it builds SWT...
9) Wait even longer...
10) The build will fail.
A collaboration to try to provide an up-to-date eclipse package for Ubuntu (and possibly Debian in general).