 <p><a href="http://checkstyle.sourceforge.net/" rel="nofollow noreferrer">CheckStyle</a> to enforce coding standard, <a href="http://cobertura.sourceforge.net/" rel="nofollow noreferrer">Cobertura</a> for checking code coverage.</p> <p>On a related note also check the book <a href="http://oreilly.com/catalog/9780596527938" rel="nofollow noreferrer">Java Power Tools</a><br> which covers around 30 open source tools that help to do better development with Java</p>