Note that alot of this information is out of date, see RestrictedFormats for more recent information.
Java for i386
Sun's Java is no longer in the hoary-extras repository, and has been taken out for legal reasons. You can build your own Java package by following the instructions on JavaPackageBuildNewVersions.
In BreezyBadger, Java is available as the Blackdown j2re1.4 and Blackdown j2se1.4 packages in the multiverse repository.
Java on other Architechtures
Ubuntu PPC, please see: ["JavaPPC"]. Ubuntu AMD64, please see: ["JavaAMD64"].
Installing the JDK
If you want to install the Java compiler as well as the runtime environment, the easiest thing to do is to [https://java.sun.com/j2se/1.5.0/download.jsp get it directly from Sun]. Take care to use the "Linux self-extracting file" version. Converting the RPM with alien will not work.
Then follow the instructions as set forth on JavaPackageBuildNewVersions to create a .deb file you can install using dpkg.