JDK(Java Development Kit): The Java Development Kit(JDK) is a software development environment used for developing Java application and also in applets. It contains JRE(Java Runtime Environment), compiler(javac), an archieve(jar file), documentation generation(javadoc) and many other tools in java development.It is physically exist and it is combination of JRE and development tools. JRE(Java Runtime Environment): Java Runtime Environment(JRE) is we say JAVA platform, All Java programs to run under the JRE. Includes JVM and JAVA core libraries and supporting files. It dows not include development tools - compilers, debuggers, and other tools, as compared to the JDK. JVM(Java Virtual Machine): Java Virtual Mechinal (JAVA virtual machine ) . JVM is part of the JRE , it is a fictional computer, through the actual computer simulation of a variety of computer functions to achieve. JVM has its own complete hardw