JRE and JDK, JVM

JRE – Java Run Time Environment

- The main usage of JRE is to run our Java Applications and Applets.
- JRE provides the libraries, the JVM, and other components, those are useful to run our Java Applications.

Other components in JRE are 

- Java Plug-In : It enables Applets to run in different kind of web browsers.
- Java Web Start : It deploys stand alone applications over a network.

JDK- Java Development Kit

JDK contains compilers and debuggers, those are useful for developing applets and our java applications, and it also contains all components that are in JRE.

JVM Memory:

The JVM Data Area (Memory) divided into 5 areas

1. Method Area
2. Heap Area
3. Java Stacks
4. PC Registers
5. Native Method Stacks


Heap Area - It's one of Runtime Data Areas. Object of the any Class will be created in Heap space.

- instance variables, instance blocks and other data in that object will be stored in this area.

- Garbage Collection will free up the memory space by removing objects which does not have any references pointing to them, and those are not used such a long time. It will increase the memory space not reduce the memory space. Garbage Collection will be done by JVM implicitly, that is one of the major advantages of Java.