Difference Between jre jvm and jdk

JDK (Java Development Kit)

JDK= JDK tools + JRE

JRE = JVM + Java Packages Classes(like util, math, lang, awt,swing etc)+runtime libraries.

JDK contains tools required to develop the Java programs, and JRE to run the programs. The tools include compiler (javac.exe), Java application launcher (java.exe), Appletviewer, etc…

JAVA Compiler converts java code into byte code. and java application launcher opens a JRE, loads the class, and invokes its main method.

If you want to write and compile your own programs, you need JDK. If you just want to run your java programs, JRE is sufficient. JRE is targeted for execution of Java files

You can create a Java file (with the help of Java packages), compile a Java file and run a java file. JDK is mainly targeted for java development.


JRE (Java Runtime Environment)
Java Runtime Environment contains JVM, class libraries, and other supporting files. It does not contain any development tools such as compiler, debugger, etc. Actually JVM runs the program, and it uses the class libraries, and other supporting files provided in JRE. If you want to run any java program, you need to have JRE installed in the system.


JVM(Java Virtual Machine)
The Java Virtual Machine provides a platform-independent way of executing code, programmers can concentrate on writing application, without having to be concerned with how or where it will run.