Java Platform

is a platform for java development. It is a software only platform which is ported on hardware platforms It comprises of two major components

1. JVM - Java virtual machine - it is the component which add portability aspect to Java. JVM understand byte codes (compiled .class files from .java classes). Byte codes are the machine language of the JVM. JVM then interprets byte codes to the actual underlying machine language. Compilation happens only once and interpretation happens each time the program is executed.
2. Java API - a set of classes written using java and which runs on the JVM. It consists of lot of useful classes which help us in development of applications etc.

You can find useful references

• http://download.oracle.com/javase/tutorial/getStarted/intro/definition.html