I'm still trying to determine an answer to my question from a few minutes ago, "Should client-server code be written in one 'project' or two?" and I think it would benefit me to see how other projects organize their code (and hopefully deduce the pros and cons of why they chose to do it that way).

What are some open source client-server projects which might be best to look at and mimic their code organization style?

Java is preferred but not required.