What is Sonar?
Sonar is a web based code quality analysis tool for Maven based Java projects. It covers a wide area of code quality check points which include: Architecture & Design, Complexity, Duplications, Coding Rules, Potential Bugs, Unit Test etc. Sonar has a rich set of features like what you would get with different tools such as Covertura, PMD, FindBugs, Check Styles combined.
Setting up Sonar