It looks interesting.
Have you actually used it to find confirmed defects in projects you are involved in? In JBoss?
IE, have you raised or seen raised an issue which was reported by this tool, and subsequently fixed by that project's dev team?
These sorts of tools are helpful, but only if the project team trusts its output enough to write JUnit tests to confirm the problem. They are probably too busy fixing bugs users actually encounter or creating features users have actually requested :-)
Looks like they already ran their tool against JBoss 4.0.2:
Seems like mostly 3rd party stuff raises warnings.
The tool integrates pretty readily with Maven:
To answer your questions: I have used it in my projects and have used it to correct some (potential) synchronization bugs. I have found issues against other people's code.
You can review the report yourself and decide on the quality of results.