Open Source CRM for a one-person business...

Now that I start being self-employed, I have to take care of existing and potential customers, to get them to hire me (by the way, if you're reading this, you could consider it?! :) ).
Apart from the obvious thing that I'll have to convince people that I can help them solve their problems and do their business, that means I must manage contacts and the actions I do with them. CRM.

Sure I have a preference for a java based system, but it's not very clear what one could chose in that area. After some research, my possible candiates are:
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