SUBJECT MATERIAL, EBOOKS, IMPORTANT QUESTION , ASSIGNMENT QUESTION, OLD QUESTION PAPER

Sunday 6 August 2017

Java Virtual Machine (JVM)

Explaination : A Virtual Machine is a software implementation of a physical machine.  Java was developed with the concept of WORA ... thumbnail 1 summary
JVM Architecture Diagram

Explaination :
  • A Virtual Machine is a software implementation of a physical machine. 
  • Java was developed with the concept of WORA (Write Once Run Anywhere), which runs on a VM.
  • The compiler compiles the Java file into a Java .class file, then that .class file is input into the JVM, which Loads and executes the class file.
 The JVM is divided into three main subsystems:
  • Class Loader Subsystem
    • Java's dynamic class loading functionality is handled by the class loader subsystem. It loads, links. and initializes the class file when it refers to a class for the first time at runtime, not compile time. 
  • Runtime Data Area
    • Method Area 
    • Heap Area 
    • Stack Area 
    • PC Registers
    • Native Method stacks
  • Execution Engine
    • The bytecode which is assigned to the Runtime Data Area will be executed by the Execution Engine. The Execution Engine reads the bytecode and executes it piece by piece.