I need either a layout manager or container that will layout components in a tree format, preferably with lines connecting parent/child. JTree doesn't work for me because it represents trees ...

Take a walk on the client side with Qt Jambi -- an alternative to Swing and Java 2D for developing rich, cross-platform desktop-application interfaces.

Which is better for your next Java GUI project: Java Swing vs. JavaFX? This tip explores their history and capabilities to help you choose the right one.