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

http://java-source.net/open-source/parser-generators and http://catalog.compilertools.net/java.html contain catalogs of tools for this. Compare also the Stackoverflow question Alternatives to Regular Expressions.