JVM and JRE

[Pawanpreet Singh]

Hi All,

What is the difference in JVM and JRE.

[Ernest Friedman-Hill]

The JVM (Java Virtual Machine) is essentially just the program java.exe, without the Java runtime libraries. You can't really do anything with the JVM by itself; you need a JRE, a Java Runtime Environment, which includes all the classes in the standard Java API.

[Bill Shirley]

good diagram:
http://java.sun.com/j2se/1.5.0/docs/

[Jesper de Jong]

The JVM (Java Virtual Machine) is just the motor. But if you want to travel somewhere, you need more than just the motor - you'll need a complete car. The JRE (Java Runtime Environment) is the car - it's the motor, with everything around it that you need to be able to use it.

[An Sush]

JVM is required for running Java programs and applications (like applets).
JRE is a level higher than JVM and it supports developement of Java code. You can run Java program(.class file) in JVM but cant compile (.java file). using JRE you can compile java (.java) and run(.class) it as well

[Campbell Ritchie]

Originally posted by An Sush:
JVM is required for running Java programs and applications (like applets).
JRE is a level higher than JVM and it supports developement of Java code. You can run Java program(.class file) in JVM but cant compile (.java file). using JRE you can compile java (.java) and run(.class) it as well

I am afraid you are mistaken.

The JRE contains a JVM, so does the JDK. Both will run Java bytecode files.

The JDK contains compiling tools, libraray classes (the API) etc., as well, so you can create new bytecode files with the JDK.

[ragha naidu]

JRE = JVM + some standard JAVA class libraries [which are used to implement API]