you can also take a look at qulice.com, which integrates together Checkstyle, PMD, FindBugs, and pre-configures them
softwarerecs.stackexchange.com will be your friend.
Will you please comment a bit on your use of lint4j? I just tried it, but it produced only a single warning (a false positive!) on my entire code base. I know my code isn't that clean! My code requires Java 6, and the lint4j proj. seems to be inactive. lint4j is not FOSS, so no source code. Thanks!
I got several hundred warnings from lint4j during my scan of 200 KLOC project. Most of them were "nice to have" like "use a character literal instead of String literal to append a single constant character to a stream". Findbugs definitely gives you the more important things to consider. (But on new code I always use both of them!)
I don't like Sonar - they began to be very very expensive.