Introduction As a lot of articles and programs require to have Java installed, this article will guide you through the process of installing and managing different versions of Java. Installing default JRE/JDK This is the recommended and easiest option. This will install OpenJDK 6 on Ubuntu 12.04 and earlier and on 12.10+ it will install OpenJDK 7. Installing Java with apt-get is easy. First, update the package index: sudo apt-get update Then, check if Java is not already installed: java -version If it returns "The program java can be found in the following packages", Java hasn't been installed yet, so execute the following command: sudo apt-get install default-jre This will install the Java Runtime Environment (JRE). If you instead need the Java Development Kit (JDK), which is usually needed to compile Java applications (for example Apache Ant , Apache Maven , Eclipse and IntelliJ IDEA execute the following command: sudo ap...