why we use jdk in java code example

Example 1: java jdk

// java JDK is a java compiler

Example 2: JDK IN JAVA

The Java Development Kit (JDK) is a software development 
environment used for developing Java applications. 
It includes:
	Java Virtual Machine, 
	Java Runtime Environment,
	Loader, 
	Java compiler, 
	Documentation generator 
	Archiver (jar), 
	Other tools needed in Java development.