Java is an object-oriented programming language developed by Sun Microsystems in the early 1990s. Java applications are compiled to bytecode, which at runtime is either interpreted or compiled to native machine code for execution.
Install java in ubuntu 10.10
Open the terminal and run the following commands
sudo add-apt-repository ppa:sun-java-community-team/sun-java6
sudo apt-get update
sudo apt-get install sun-java6
Ubuntu 10.04(Lucid) users also can install java using this PPA