Installing OpenJDK in Ubuntu

Run the Command :

apt-get install openjdk-7-jdk

Inorder to verify the installation of java in Linux :

$ which java

   or

$ java -version
java version "1.7.0_09"
OpenJDK Runtime Environment (IcedTea7 2.3.3) (7u9-2.3.3-0ubuntu1~12.10.1)
OpenJDK 64-Bit Server VM (build 23.2-b09, mixed mode)
mkyong@yong-ubuntu:/usr/lib/jvm/java-7-openjdk-amd64/bin$