This tutorial shows you how to install Java on CentOS 7. Java is one of the most popular programming languages used to build different kinds of applications and systems. There are two different Java packages, Java Runtime Environment (JRE) and the Java Development Kit (JDK). If you only want to run Java programs then you need JRE and if you are Java developer then you will need JDK which includes JRE and development/debugging tools and libraries. There are also two different implementations of Java, OpenJDK and Oracle Java with almost no differences between them except that Oracle Java has a few additional commercial features.