What’s the difference between JDK and JRE?

While the Java Runtime Environment (JRE) is a set of libraries and programs which enables the final user to run Java applications, the Java Development Kit (JDK) is a product aimed at Java developers. With the JDK we are able to develop, debug and run a Java application on any platform.

The JDK has a lot of components, but the main are:

 javac

A compiler which converts source code (text files with extension .java) to a bytecode file (mainly .class files)

java

It´s the loader for Java applications. It interprets the bytecode file generated by javac compiler to the operational system.