Enumerate the concept of write once run anywhere - JAVA

Java has introduced concept of WORA (write once run anywhere). When you write a java program it is called source code of java. Java compiler doesn't compile this source code for any underlying hardware system; rather it compiles it for a software system called JVM (This compiled code is called byte code). We have different JVMs for different systems (for example JVM for Windows, JVM for Linux etc.). When we run our program the JVM interprets (translates) compiled program into the language understood by underlying system. So we write our code once and JVM runs it everywhere according to the underlying system.