FindBugs

A static analysis tool to find bugs in Java programs.

FindBugs is an easy to use program designed to help you find the bugs that a Java programs might have.

FindBugs requires JRE (or JDK) 1.5.0 or later to run. However, it can analyze programs compiled for any version of Java, from 1.0 to 1.8. It works on Windows operating system.