JVM,JRE and JDK In Java

 JVM

The Java Virtual machine  (JVM)   is the virtual machine that runs the java bytecodes.Therefore you need to compile your Java application (.java) so that it can be converted to bytecode format (also known as the .class file)  then it will be used by JVM to run application.

The JVM performs following tasks:

• Loads code
• Verifies code
• Executes code
• Provides runtime environment

JRE 

The Java Runtime Environment is an installation package which provides environment to only run the java program onto your machine.

JRE = JVM + Required Library Classes to run Application.

JDK 

The Java Development Kit is a Kit (or package) which provides the environment   to develop and execute the Java program. JDK includes following things:

Development Tools: used to provide an environment to develop java applications

JRE: used to execute or run java applications.

JDK = JRE +  development Tools.