Bytecode in Java is a highly optimized set of instructions that can be executed on any platform with a Java Virtual Machine (JVM) installed. When you compile Java source code, the resulting output is not machine code that can be executed directly by the operating system, but rather a bytecode that can be executed by a JVM.
Java is called platform-independent because of its ability to compile Java code into bytecode that can be run on any platform that has a JVM installed. This is in contrast to languages like C or C++, where code is compiled directly into machine code that is specific to a particular hardware and operating system platform.
When a Java program is compiled, it is compiled into bytecode that is platform-independent. This means that the same bytecode can be executed on any platform with a JVM installed, regardless of the underlying hardware and operating system. The JVM is responsible for interpreting the bytecode and executing it on the host platform, providing a layer of abstraction that isolates the program from the underlying hardware and operating system.
This platform independence makes Java a highly portable language, allowing programs to be developed on one platform and then deployed on any other platform with a JVM installed, without requiring any modifications to the code. This is a significant advantage for developers who need to write software that can run on multiple platforms without having to maintain multiple versions of the code.