JDK

Install Sun Java 6 JRE and JDK from .deb packages
Install Sun Java 6 JRE and JDK from .deb packages

An alternative approach to install Sun Java 6 on Ubuntu

Sun Java 1.6.0.30 packages for Ubuntu
Sun Java 1.6.0.30 packages for Ubuntu

Get Sun Java 1.6.0 packages from a PPA