What is difference between JVM, JRE, and JDK ?

Difference between JDK JRE and JVM:

Understanding the difference between JDK, JRE and JVM is important in Java. We will have
brief overview of JVM here. If you want to gain the detailed knowledge of JVM...., move to the next
page. First, let's see the basic differences between the JDK, JRE and JVM.

JVM(Java Vertual Machine):

JVM (Java Virtual Machine) is an abstract machine.It is a specification that provides runtime environment in which java bytecode can be executed. JVMs are available for many hardware and software platforms (i.e.JVM is plateform dependent).

The JVM performs four main tasks:

> Loads code
> Verifies code
> Executes code
> Provides runtime environment

JRE(Java Runtime Environment):

JRE is an acronym for Java Runtime Environment.It is used to provide runtime environment.It is the implementation of JVM. It physically exists.It contains set of libraries + other files
that JVM uses at runtime.It contains JVM,set of libararies ( e.g.rt.jar,charsets.jar,jsse.jar ect.)
and other files.

JDK(JavaDevelopment Kit):

JDK is an acronym for Java Development Kit. It physically exists.
It contains JRE + other development tools(e.g.javac,javap,java etc)

Note: You can see JDK in you system under  C:\Program Files\Java\jdk1.6.0_18   folder.
 here C is a drive where Java is install.