JVM
JVM is an acronym for Java Virtual Machine.it is an abstract machine that
provides runtime environment in which java bytecode can be executed.
The JVM performs following main tasks:
1 Loads code
2 Verifies code
3 Executes code
4 Provides runtime environment
JRE
1 JRE is an acronym for Java Runtime Environment.It is used to provide
runtime environment.It physically exists.
2 JRE is an implementation of the Java Virtual Machine which actually
executes Java programs.
3 Java Runtime Environment is a plug-in needed for running Java programs.
4 JRE is smaller than the JDK so it needs less disk space.
5JRE includes the JVM, Core libraries and other additional components to
run applications and applets written in Java.
JDK
1JDK is a bundle of software that is used to develop Java based
applications.
2Java Development Kit is needed for developing Java applications.
3JDK needs more disk space as it contains the JRE along with various
development tools.
4 JDK includes the JRE, set of API classes, Java compiler, Webstart and
additional files needed to write Java applets and applications.