How to install Sun Java 1.5 on Ubuntu 10.04 Add the following to /etc/apt/sources.list: deb http://us.archive.ubuntu.com/ubuntu/ jaunty multiverse deb http://us.archive.ubuntu.com/ubuntu/ jaunty-updates multiverse Update the package list: sudo apt-get update Install Sun Java 1.5: sudo apt-get install sun-java5-jdk Depending on your setup you might need to set this as the default. Check what version is default: java -version And list all Java versions installed: sudo update-java-alternatives -l Then if necessary: sudo update-java-alternatives -s java-1.5.0-sun If you want to get Sun Java 1.6 installed, instead of OpenJDK, just enable the partner repositories in the Package Manager > Software Sources and it will show up in the list for you to install.