Why is Java called platform independent?

javac does not produce machine code for one processor. It produces bytecode — instructions for an abstract machine, stored in .class files. Any computer with a JVM for its OS and CPU can run that same bytecode.

Hello.java --javac--> Hello.class (bytecode) --JVM on Windows / Linux / macOS--> runs

So the program is platform independent, but the JVM is not: each platform needs its own JVM build. Portability also depends on the code itself — hard-coded file paths like C:\data, OS-specific line endings or native (JNI) libraries can still tie a program to one platform.