GNU Aspell is a Free and Open Source spell checker designed to eventually replace Ispell. It can either be used as a library or as an independent spell checker.
Java implementation of the statistical spelling checking algorithm by Peter Norvig which he described in his Essay "How to write a Spelling Corrector".
W. Cushman, P. Ojha, and C. Daniels. CHI '90: Proceedings of the SIGCHI conference on Human factors
in computing systems, page 145--152. Association for Computing Machinery (ACM), (1990)