checkstyle

Jenkins is an excellent choice for continuous integration as it has numerous plugins available, is well supported and is open source.

The following is a list of some of the most useful plugins and how they can be used.

GIT Plugin

I'm a great believer in getting quality in as early as possible in the development cycle. Checks that run automatically in an IDE are best (for example the Checkstyle/PMD plug-ins in Eclipse).

But these have one drawback: they are not enforced.