There's a setToggleClickCount( int ) method that sets how many clicks it takes to make the tree nodes of a tree to expand.
If you need to do something else, you can just attach a MouseListener and get the number of clicks by calling getClickCount() on the MouseEvent. ( In fact, there is an example of this in the JavaDocs for JTree. )
Write once, run anywhere, because there's nowhere to hide! - /. A.C.