JAVA : PLATFORM DEPENDENCY AND IN-DEPENDENCY

Hey everyone !! In my previous post I have discussed about some basic terminologies about java and the next topic is Platform Dependency and In-dependency. In this post I will explain you all that actually what is a platform, why java is called platform independent language, why c and c++ are not in this category.

PLATFORM:

It is an environment in which a program is loaded and executed, and the output is generated. The platform can be a software based or hardware based.

C program is compiled by OS. It means that C programming compiled code is directly executed by the OS. C++ is the advance version of C language only so the c++ program platform is also OS. Its code is also executed by OS

Java Program platform is JVM i.e. Java Virtual Machine. It means java program compiled code is executed by special software called JVM, but not by operating system. To run java program in our system we must install JVM.

Note:- We call java a platform Independent language but the JVM software is a platform dependent i.e. if you want to run java in your system you must install JVM which supports the OS which is installed in your system. Sun Microsystems has designed JVM for all the software's which is available in the market.

.NET program platform is CLR. It means .net program compiled code is executed by a special software called CLR but not by the operating system directly.

PLATFORM DEPENDENCY :-

A simple program that we develop and compile in one Operating System, if it is not executed in different Operating System then we called the program as platform dependent program and the language using which we develop this program is called platform dependent language.

In simple words if I want to elaborate it, it will be like suppose there is a group of friend of five people. One person is has develop a code in his system and also executed it also if he give the same code to his friend so that he can also have a look towards it. But when his friend open that code it is not executable. This is because both the machines are different so the same code can't be run on another machine. This is called platform dependency.

The above figure illustrates that we have develop a program in windows operating system and it can only be executed in windows OS only not in any other OS.

PLATFORM INDEPENDENCY:-

This is just the opposite case of the previous one. Suppose if we are developing a program and it is executed in any other operating system then we call it as a platform independent program and the language which is used to develop this program is called as platform independent language. This concept can be illustrated from the given diagram.

In this diagram we have developed a program in Windows Operating system and with the help of JVM it is executed in any other os. Just the requirement is That particular Operating System must have JVM installed.

WHY C AND C++ LANGUAGE ARE PLATFORM DEPENDENT :-

C and c++ compiled code is machine language of current Operating System in which it is compiled one operating system machine language code is different from other operating system machine language format. The compiled code in one operating system will not be executed in other operating system.

Not only C program , C software is also platform dependent because C software contains compiler, linker and header files, all these components are platform dependent so C software becomes platform dependent. Let me explain this with you a diagram

HOW JAVA ACHIEVED PLATFORM INDEPENDENCY :-

Java achieved platform in-dependency " By moving machine language generation from compilation phase to execution phase. For this new compiler software, byte code and java virtual machine are introduced in java" i.e. Java has introduced a new concept of jvm which runs the byte code generated by java compiler and the output is generated irrespective of the operating system.

In java machine language is moved from compilation phase to execution phase, because machine language should generate for client Operating System to execute programming in client computer, client Operating system information information  we will get at the time of execution time. Let me explain all this with the help of a diagram

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