Java platform is a software-only platform independent, which runs on top of other hardware-based platforms like WINDOWS, UNIX, NT etc.
The Java platform has 2 main components:
1. Java Virtual Machine (JVM ) - 'JVM' is software that will be ported onto various hardware platforms or on various operating systems. Byte codes are the machine language code of the Java virtual machine.
2. Java Application Programming Interface (Java API ) - set of classes written using the Java language and run on the JVM which installed on operating system.