This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
There isn't enough information here to say much. It seems like you'd test the main logic in one and the integration/interface in the other. After all, the war would contain the jar so much of the code is the same.