What is JVM?

Acronym for Java Virtual Machine:  An abstract computing machine, or virtual machine,
JVM is a platform-independent execution environment that converts Java bytecode into
machinelanguage and executes it Most programming languages compile source code directly into machine code that is designed to run on a specific microprocessor architecture or operating system, such as Windows or UNIX. A JVM -- a machine within a machine -- mimics a real Java processor, enabling Java bytecode to be executed as actions or operating system calls on any processor regardless of the operating system. For example, establishing a socket connection from a workstation to a remote machine involves an operating system call. Since different operating systems handle sockets in different ways, the JVM translates the programming code so that the two machines that may be on different platforms are able to connect.

Role of JVM:

a)  Loading of class files.

b)  Verification of class files i.e. Class files should contain valid bytecode. As java is
strictly type check language. So syntax checking and either code is reachable or not
will be checked at compile time.

c)  Interpretation of byte code and then run the program.