How to draw a tree representing a graph of connected nodes?

You might consider any of these:

• JHotDraw, cited here, a meta-library for creating custom graph editors.

• Prefuse visualization library, illustrated here and here.

• Batik, which implements SVG rendering.

• JGraph demo and user manual.

• GraphStream, illustrated here.

• JFreeChart XYBubbleRenderer

• A JTree, suggested here, with a custom TreeIcon.

• A custom renderer, with x based on a fraction of tree breadth and y based on recursion level.

• A simple graph editor such as draw.GraphPanel, illustrated here.