JVM does not compile Java source code to byte code. It is 
the Java Compiler which does that. JVM runs on the target 
machine which interprets the byte code and runs the program 
on the target machine.   

Java is not platform independent. Though you write the Java 
source code, somebody else ( Sun Microsystems ) have done 
the hardwork to implement JVM for the platform which is 
going to run your program. "Java is Platform Independent" 
is an illusion.