How exactly does java compilation take place?

Question

Confused by java compilation process

OK i know this: We write java source code, the compiler which is platform independent translates it into bytecode, then the jvm

Answer 1

Windows doesn't know how to invoke Java programs before installing a Java runtime, and Sun chose to have native commands which collect arguments and then invoke the JVM instead of binding the jar-suffix to the Java engine.

Answer 2

Well, javac and the jvm are typically native binaries. They're written in C or whatever. It's certainly possible to write them in Java, just you need a native version first. This is called "boot strapping".

Fun fact: Most compilers that compile to native code are written in their own language. However, they all had to have a native version written in another language first (usually C). The first C compiler, by comparison, was written in Assembler. I presume that the first assembler was written in machine code. (Or, using butterflies ;)

.class files are bytecode generated by javac. They're not textual, they're binary code similar to machine code (but, with a different instruction set and architechture).

The jvm, at run time, has two options: It can either intepret the byte code (pretending to be a CPU itself), or it can JIT (just-in-time) compile it into native machine code. The latter is faster, of course, but more complex.

Answer 3

1. .java file
2. compiler(JAVA BUILD)
3. .class(bytecode)
4. JVM(system software usually build with 'C')
5. OPERATING PLATFORM
6. PROCESSOR