Red Hat has spent the last couple of years dealing with a lawsuit from Firestar (later DataTern) concerning alleged patent infringement in their
JBoss product. The details of the patent are not especially important at this point - what's pertinent is that Red Hat apparently paid the problem to go away, while preserving in the settlement (according to their own
FAQ) broad freedom for the open source community. Now that they've released the actual
settlement details, we can see how well they stack up.