AJava virtual machine (JVM) is a set of computersoftware programs and data structures which use avirtual machine model for theexecution of othercomputer programs andscripts. The model used by aJVM accepts a form of computerintermediate language commonly referred to asJava bytecode.
Java virtual machines operate on Javabytecode, which is normally (but not necessarily) generated fromJavasource code; a JVM can also be used to implement programming languages other than Java.
TheJVM is an important component of theJava Platform. BecauseJVMs are available for many hardware and softwareplatforms, Java can be bothmiddleware and aplatform in its own right – hence the expression "write once, run anywhere." The use of the same bytecode for all platforms allows Java to be described as "compile once, run anywhere", as opposed to "write once, compile anywhere", which describes cross-platformcompiled languages.
