I\'m working on a Java web application that integrates with a few other external applications that are deployed along with it. Authentication information must be synchronize
As this question has been unanswered for quite some time, I'd like to suggest that you also take the commercial license of Penrose into account - it's got a dual license for people just like you, when the GPL implications are prohibitive. I don't know their prices and model, but it might be easier and cheaper to go with a solution that you already know than to get used to another solution that you need to get used to. You can either pay with your money or with your time...
Also - for the records, not applying in this case: When projects use the GPL and you'd like to embed them in a non-GPL way, it might pay to ask the developers for a more permissive license. Some people publish under GPL not thinking about the implications. You might get them to changing the license if this means broader usage of the project. Others specifically want the GPL-implications, but it's always good to ask. Penrose has already thought about this and offers a commercial license.