How can I parse code to build a compiler in Java?

Question

I need to write a compiler. It\'s homework at the univ. The teacher told us that we can use any API we want to do the parsing of the code, as long as it is a good one. That way

Answer 1

Go classic - Lex + Yacc. In Java it spells JAX and javacc. Javacc even has some Java grammars ready for inspection.