Platform-independent means that java compiled code (bytecode) can run on all operating systems. The program is written in a human-readable language. It may contain words, phrases, etc. that the machine cannot understand. For the source code that the machine can understand, it needs to use a language that the machine can understand, usually a machine-level language. Therefore, the role of the compiler has come. The compiler converts the high-level language (human language) into a format that the machine can understand. Therefore, a compiler is a program that translates the source code of another program from a programming language into executable code. This executable code may be a series of machine instructions that can be directly executed by the CPU, or it may be an intermediate representation interpreted by a virtual machine. This intermediate representation in Java is Java bytecode.

Step by step Execution of Java Program:

• Whenever a program is written with JAVA, javac will compile it.
• The result of the JAVA compiler is a .class file or bytecode, not machine native code (unlike a C compiler).
• The generated bytecode is non-executable code and requires an interpreter to execute on the machine. This interpreter is JVM, so the bytecode is executed by JVM.
• Finally, the program runs to provide the required output.

For C or C++ (non-platform independent languages), the compiler generates an .exe file that depends on the operating system. When we try to run this .exe file on another operating system, it will not run because it depends on the operating system and therefore is not compatible with other operating systems.

Java is platform-independent but JVM is platform dependent

In Java, the point here is that the JVM depends on the operating system-so if you are running Mac OS X, you will have a different JVM than running Windows or other operating systems. This fact can be verified by trying to download a JVM for your specific machine-when you try to download it, you will get a list of JVMs corresponding to different operating systems, and you will obviously choose the JVM for the operating system you are running. So we can conclude that JVM is platform dependent, which is why Java can become "platform independent".

Important Points:

• As far as Java is concerned, the magic of bytecode is to make it platform independent.
• This adds an important feature called portability in the JAVA language. Each system has its own JVM, which will be installed automatically when the jdk software is installed. Each operating system has an independent JVM that can read .class files or bytecodes.
• The important thing to note is that although JAVA is a platform-independent language, JVM is platform-dependent. Different JVMs are designed for different operating systems, and the bytecode can run on different operating systems.