This week a colleague (Sven) and me tried to get a complex swing widget running: a TreeTable. This component is a JTable with an JTree in its first column. If you do a google search you'll find an fairly old article at suns site which includes sources with this JTreeTable. Unfortunatly their example how to use this treetable is a full blown file explorer. Additionally their AbstractTreeTableModel is just bad implemented.
So if you want to start with a JTreeTable get the sun sources and try the following example: TreeTableEasyExample.java.