It is probably a bit late now, and I suppose you must have moved on with your project. But you can anyways check this blog out. It has a series of posts on nlp with java. Stanford-NLP, as suggested by others is a great library to work with.
Most of the libraries will help you in the lexical analysis phase (sentence segmentation, tokenization, POS tagging, parsing, etc.) so that you don't have to start your code from scratch. All the best !
