yEd - Java Graph Editor: "yEd is a very powerful graph editor that is written entirely in the Java programming language. It can be used to quickly and effectively generate drawings and to apply automatic layouts to a range of different diagrams and networks. yEd is available as a free download with unrestricted functionality!
yEd makes full use of the yFiles library. This is a Java class library enabling the viewing, editing, optimizing, drawing, and animating of a wide range of diagrams, networks, and other graph-like structures.
yEd has been built using 100% lightweight Swing components. This allows it to run on any platform where a suitable Runtime Environment is available.
Outstanding Features
yEd can be used to automatically lay out complex graph structures. Several highly sophisticated layout algorithms have been implemented and shipped with yEd. They can be used either to automatically arrange the items or to support the user when undertaking a manual layout."
