I'm looking for a free Java library to visualize some data. I want to do something similar as the following two images. Is there any possibility? I first thought of prefuse, but this isn't developed since 2007. So any oher libraries?
Have you considered looking at GraphViz?
Graphviz (short for Graph Visualization Software) is a package of open-source tools initiated by AT&T Labs Research for drawing graphs specified in DOT language scripts. It also provides libraries for software applications to use the tools. Graphviz is free software licensed under the Eclipse Public License.
You can do some fairly cool stuff with it: