Java Virtual Machine and Byte Code

Learning a basic program Hello World! Would have given you an idea of the simple structure of a Java Program.

Now let us see how the javac compiler actually compiles your program and translates your High level source code into Byte code and is passed to java Interpreter. So before going any further let us discuss what exactly is Byte code.

The Byte Code:

Byte code is an intermediate code which is given by the javac compiler after compiling the java program. The specialty of Byte code is that it is machine Independent, i.e. the byte code can run on Windows, Mac, Linux etc or any of the machines that exist.

To be clear let me give an example.

Suppose you have Windows OS installed on your computer and you even need Linux OS for some work of your choice, but you are not interested in dual booting the above mentioned Operating systems so the another option you have is to use a Virtual machine to get your job done.

But in Java it already has JVM(Java virtual machine) built in it. This makes the java as Platform independent and so while installing Java on your system the JVM gets automatically configured and the byte code given by the compiler is passed to JVM or Java Interpreter(in a same way) .This interpreter translates the byte code to machine code and executes the program.

The below picture tries(in a way) to show the above metioned scenario. 

In the next post we will cover how we use some simple math functions in java program.