Question

I am developing a small desktop application in JAVA using Netbeans. I place a JTree and dynamically populating it. Every thing went fine now i want to achieve the following two things:

1. When the JTree is poupulated it will automatically expanded means
   it will start showing all of its nodes till the leaf level
2. The first leaf node should be
   selected by default.

How do i achieve these two behaviors?

Answer 1

Expand all nodes (arbitrary depth):

for (int i = 0; i < tree.getRowCount(); i++) {
    tree.expandRow(i);
}

Select first leaf:

DefaultMutableTreeNode firstLeaf = ((DefaultMutableTreeNode)tree.getModel().getRoot()).getFirstLeaf();
tree.setSelectionPath(new TreePath(firstLeaf.getPath()));