The most unique feature of java is platform independent. In any programming language source code is compiled in to executable code. This cannot be run across all platforms. When javac compiles a java program it generates an executable file called .class file.
class file contains byte codes. Byte codes are interpreted only by JVM’s . Since these JVM’s are made available across all platforms by Sun Micro systems, we can execute this byte code in any platform. Byte code generated in windows environment can also be executed in Linux environment. This makes java platform independent.