JDK( Java Development Kit)
JDK provides an environment to develop Java applications and applets. It is the Java world's main package containing JRE( Java Runtime Environment) that contains JVM(Java Virtual Machine ).
JDK = JRE(JVM + Library classes ) + Development Tools
It physically exists. If you need to run a Java program then you can do it with JRE only but if you are going to develop Java-based software then you need JDK( including JRE and additional Libraries and tools).
JDK is implemented by on the the following Java Platforms released by Oracle Corporation
- Standard Edition(Java SE)
- Java Enterprise Edition(Java EE)
- Java Micro Edition(Java ME)
Components of JDK