Why is java both compiled and interpreted [duplicate]

Question

Possible Duplicate:
Is Java a Compiled or an interpreted programming language?

Why is Java both compiled and interpreted language?

We first compiles the java program using javac(compiling) and the run the program using java(interpreting). What is the advantage of that?

Also, where does JIT role come into the picture?

Answer 1

Compile once and run anywhere is one of the reasons.

JVM is OS specific. So, JVM interprets compiled .class (byte code) file and converts into machine specific instruction set.