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.
Daniel, Eclipse will just use the first one it finds. Since they are both 1.4 versions, you should be fine.
This does introduce the question of why you need/want to versions of 1.4 on your classpath. An application will only find one so the other is just taking up space. Might be time to do a little clean up.