As a beginner java learner, I would be grateful if some people could point out a few open source projects with a high quality code base. Not necceserily aimed at a beginner, I would rather see a professional quality example, and preferabbly the project would use some common tools for java, javadoc, build tools - gradle or maven as I'm going to learn one of these two - and either svn or github for revision control. I hope I'm not asking too much there, but I'll take what I can get! I would like to have a browse through some good code and take a break from examples that for the sake of simplicity use poor practices.
p.s I currently only have windows installed.