JRE Structure

Pictorial Representation of the JRE(Java Runtime Environment)

1.) Class Loader:

Class Loader is a subsystem of JVM that is used to load class files.

2.) Class (Method) Area:

Class(method) Area stores pre-class structures such as runtime constant pool, field and method data , the code for methods.

3.)Heap:

It is the run time data area in which objects are allocated

4.)Stack:

Java Stack stores frames. It holds local variable and partial results, and plays a part in method invocation and return.

Each thread has a private JVM stack, created at the same time as thread.

A new frame is created each time a method is invoked. A frame is destroyed when its method invocation completes.

5.)PC(Program Counter) Register:

It contains the address of the java virtual machine instructions currently being executed.

6.)Native Method Stack:

It contains all the native methods used in the application.

7.)Execution Engine:

It contains :

• A Virtual Processor
• Interpreter
• Just-In-Time (JIT) compiler