Getting JScrollPane to resize with container...

Question

I am tearing my hair out trying to get a JScrollPane containing a JTree to properly resize when its parent container is resized (and indeed to be sized properly when first added to the container).
Currently, the scrollpane sizes itself to its child (tree), which is much larger than the preferred size of the containing JPanel. consequently no scrollbars are shown, and the tree is centered in the display.
Any help greatly appreciated!
A minimal example of code that behaves badly in this respect follows:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
//ScrollTest.java
import java.awt.BorderLayout;
import java.awt.Dimension;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;
import java.awt.event.WindowAdapter;
public class ScrollTest{
public static void main(String[] args){
DefaultMutableTreeNode top = new DefaultMutableTreeNode("TEST");
DefaultMutableTreeNode curNode = top;
JTree jt = new JTree(top);
StringBuffer sb = new StringBuffer("TEST:");
for (int i=0;i<10;i++){
DefaultMutableTreeNode n = new DefaultMutableTreeNode(sb.toString());
curNode.add(n);
curNode = n;
sb.append(sb.toString());
jt.expandRow(i);
JScrollPane jsp = new JScrollPane(jt);
JPanel jp = new JPanel();
jp.setPreferredSize(new Dimension(200,200));
jp.add(jsp,BorderLayout.CENTER);
JFrame jf = new JFrame("Test");
jf.setContentPane(jp);
jf.addWindowListener(new WindowAdapter(){
public void windowClosing(){
System.exit(0);
jf.pack();
jf.show();
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Answer 1

ok: don't set the the content pane.
add the JPanel to the content pane: getContentPane.add(jp, BorderLayout.CENTER);
(the content pane of a JFrame has a BorderLayout by default), that way your scroll pane should resize automatically when and if you resize the JFrame.
thomas