I'm not asking for anything fancy - just an example of a Java codebase that is "good" for whatever definition of "good". I'm currently dabbling in Android deve

I'm not asking for anything fancy - just an example of a Java codebase that is "good" for whatever definition of "good". I'm currently dabbling in Android development, and the few Java libraries I've dealt with, especially Android's own APIs, have been a thorough exercise in frustration, to put it mildly. Where are the good Java codebases hiding?