Wikipedia Entry: Java is a general-purpose computer-programming language that is concurrent, class-based, object-oriented, and specifically designed to have as few implementation dependencies as possible. It is intended to let application developers "write once, run anywhere" (WORA), meaning that compiled Java code can run on all platforms that support Java without the need for recompilation. Java applications are typically compiled to bytecode that can run on any Java virtual machine (JVM) regardless of computer architecture. Java has 2 primary components necessary to write and run Java code, this is the JRE and the JDK. The JRE is Java's Runtime Environment and is the thing that actually executes Java's bytecode on a specific machine. It is what enables the WORA aspect of Java. The JDK contains a JRE as well as other code necessary to run a specific version of Java, either Java SE, EE, or ME.