JDK AND JRE

JDK (Java Development Kit)

All the programs which are required for developing a java application, compiling a java application, debugging a java application, executing a java application and also the collection of basic libraries together is known as JDK. JDK is nothing but collection of programs which are ultimately required for developing and executing a java application. Java developers need JDK for developing a java application. JVM is also a part of JDK.

JRE (Java Runtime Environment / Engine)

JVM along with the corresponding libraries is known as JRE. JRE can only execute the bytecode, because of this reason clients need only JRE for executing a java application(Byte code).