The Checker Framework

The Checker Framework enhances Java's type system. This lets software developers detect and prevent errors like null pointer exceptions, unintended side effects, SQL injections, concurrency errors, mistaken equality tests, and other run-time errors that appear during testing or in the field in their Java programs. The Checker Framework includes compiler plug-ins ("checkers") that find bugs or verify their absence. It also permits you to write your own compiler plug-ins.