We all recommend from time to time that folks pick some open source project that they are interested in and contribute to it in some way as a way to practice their Java skills and gain some experience of working as part of a team. GitHub seems to be where all the cool kids hang out these days so I thought I'd have a look around and see if I could find something of interest that I could work with.
But... I don't really know how to go about it at all. Is there a place where I can see projects that are looking for help? Or do you just find one and just get stuck in with the hope that the project owners don't just tell you to get lost?
Does anyone have some experience with this sort of thing that they could share?
A lot of the projects on github are just people showing their code and not projects that you can contribute to. By contrast, many projects on apache.org and sourceforge.net wants contributors. You can often tell by looking at the release notes, contribution history, bug list, etc.
My usual advice is to pick a project that you use and like yourself, one where you look forward to new releases. Involvement in an OSS project should be a long-time thing, and you'll more likely be interested in something that you use. SourceForge used to have a page listing projects actively looking for help, but I don't have the URL handy.
Once you've picked something, start hanging out in the developer's mailing list to see what the issues are, maybe introduce yourself, and see if there's something you could help with.
The best place to find interesting OSS is the Apache Software Foundation. They have well over 100 projects and I'm quite convinced that you will find something interesting. It definitely takes some time to get active as a commiter, but the effort is worth it.