I don't see SymmetricDS listed yet. It is an open source (LGPL) Java-based database synchronization system. It is under active development and has been around for a while. It is similar in many ways to Microsoft's Sync Framework. One difference is that it will auto-create the triggers it needs to capture the data. I seriously considered using this for my next project, but we are a Microsoft shop and will probably go with MSF.
