The latest version that I am aware of is the 3rd edition. It is a collection of C++ implementations. If you are looking for a Java math library, you may consider SuanShu.
SuanShu has already covered a lot of topics found in Numerical Recipes and uses different algorithms and/or implementaions to code in a solidly object-oriented way.
SuanShu is also a Java statistical library. It has many standard distributions, hypothesis testing, regressions, and more.
SuanShu has also thousands of test cases that run daily to ensure its quality.