Java Overview
The core Java platform is the Java 2 Platform, Standard Edition or J2SE. At the foundation of the J2SE Platform is the Java Runtime Environment (JRE). The JRE runs the applications and applets coded in Java on a variety of platforms The second major component of the J2SE is the Java 2 Software Development Kit (SDK). It contains the JRE along with several other tools for developing Java applications and other applets. These tools include the Java compiler and debugger. The first step in creating a Java application is writing the Java source code in a text editor. Before you run the Java program that you have created, you need to compile it. You can do this using any machine that has a Java compiler installed.