Anyway, I decided that I need something, preferably an Eclipse-plugin to visualize class dependencies, and there are actually a few options:

• X-Ray would probably do the job, but it doesn't work. Maybe I just don't know how to install it correctly.
• Byecycle have a great screencast on their page and more friendly installation instructions. It shows a dependency graph between classes and automatically and incrementally optimizes the graph layout. Infinitely. Using 20% of your processor(s). It's quite slow and it seems to be limited to only show dependencies within the package, while the dependencies I'm interested in often cross dependency boundaries (classes from different packages implementing an interface).