Checkstyle - Checks Java coding standard

Checkstyle is a tool to help programmers write Java code that adheres to a coding standard. Checkstyle is highly configurable and can be made to support almost any coding standard. Checkstyle provides checks that find class design problems, duplicate code, or bug patterns like double checked locking. This tool could be integrated as Ant task.

Plugins are available for Eclipse, Netbeans, QALab, Emacs etc.