Here a list of BioJava groups on various social networking sites:
The BioJava facebook group can be found at http://www.facebook.com/home.php#/group.php?gid=53562049203 . It is open for anybody to join.
There is a BioJava group on LinkedIn:
Developers of the BioJava open-source bioinformatics project.
To join the BioJava linkedin group: You need to be a linkedin member. You then need to find the group and ask to join. You don’t need to be a contributor just a user or interested party.
The open source social networking site Ohloh has a BioJava project page at http://www.ohloh.net/p/biojava