Download of JML.5.5_rc1.tar.gz (JML.5.5_rc1.tar.gz ( external link: SF.net): 13,406,778 bytes) will begin shortly. If not so, click link on the left.
The Java Modeling Language (JML) is a behavioral interface specification language that can be used to specify the behavior of Java modules (as in design by contract -- DBC). It has many tools to do assertion checking, unit testing, etc.