Java’s Magic: The Bytecode

The secrets behind the security and portability of Java is that the output of a Java computer is not executable code.Rather, it is Bytecode  

Bytecode is a highly optimized set of instructions designed to be executed by the Java run-time system, which is called the Java Virtual Machine (JVM)

JVM is an interpreter of Bytecode        

Java systems contain:

-Environment

-Language

-APIs

-Class libraries

Java programs normally undergo five phases

(1)    Edit

-Programmer writes program )and stores program on disk)

(2)    Complete

-Compiler creates bytecodes from program

(3) Load

-Class loader stores bytecodes in memory

(4)Verify

-Verifier ensures bytecodes do not violate security requirements

(5)Execute

-Interpreter translates bytecodes into machine language

Benefits of Bytecode

-Translating a Java program into Bytecode helps makes it much easier to run a program in a wide variety of environments

-Only JVM needs to be implemented for each platform

-Once the run time package exists for a given system, any java program can run on it

      

Posted in: CONCEPTS