Why are compiled Java class files smaller than C compiled files?

Question

I would like to know why the .o file that we get from compiling a .c file that prints \"Hello, World!\" is larger than a Java .class file that also prints \"Hello, World!\"?

Answer 1

C programs, even though they're compiled to native machine code that runs on your processor (dispatched through the OS, of course), tend to need to do a lot of set up and tearing down for the operating system, loading dynamically-linked libraries like the C library, etc.

Java, on the other hand, compiles to bytecode for a virtual platform (basically a simulated computer-within-a-computer), which is specifically designed alongside Java itself, so a lot of this overhead (if it would even be necessary since both the code and the VM interface is well-defined) can be moved into the VM itself, leaving the program code to be lean.

It varies from compiler-to-compiler, though, and there are several options to reduce it or build code differently, which will have different effects.

All this said, it's not really that important.