Java Graphing framework. LGPL

JGraph 5.12.0.0 is a free, mature, and robust Java Graphing framework that fully complies with Swing design principles. It contains all the graph visualization and interaction functionality you might expect in a graph library, including multiple views, layering, zoom, drag and drop, undo, automatic expanding and collapsing, routing, and layouts. You can create stunning workflow editors, call graphs, CAD tools, network diagrams, database visualization tools, and more. It can also be deployed on the server-side with a large range of image exporting functionality. It is fully documented and commercially supported.