code for Set tree DropMode to DropMode.USE_SELECTION in java

import java.awt.BorderLayout;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.IOException;

import javax.swing.DropMode;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import javax.swing.JTree;
import javax.swing.TransferHandler;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.TreePath;

public class DndTree {
public static void main(String args[]) {
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

JPanel top = new JPanel(new BorderLayout());
JLabel dragLabel = new JLabel("Drag me:");
JTextField text = new JTextField();
text.setDragEnabled(true);
top.add(dragLabel, BorderLayout.WEST);
top.add(text, BorderLayout.CENTER);
f.add(top, BorderLayout.NORTH);

final JTree tree = new JTree();
final DefaultTreeModel model = (DefaultTreeModel) tree.getModel();
tree.setTransferHandler(new TransferHandler() {
public boolean canImport(TransferHandler.TransferSupport support) {
if (!support.isDataFlavorSupported(DataFlavor.stringFlavor) || !support.isDrop()) {
return false;
}
JTree.DropLocation dropLocation = (JTree.DropLocation) support.getDropLocation();
return dropLocation.getPath() != null;
}

public boolean importData(TransferHandler.TransferSupport support) {
if (!canImport(support)) {
return false;
}
JTree.DropLocation dropLocation = (JTree.DropLocation) support.getDropLocation();
TreePath path = dropLocation.getPath();
Transferable transferable = support.getTransferable();

String transferData;
try {
transferData = (String) transferable.getTransferData(DataFlavor.stringFlavor);
} catch (IOException e) {
return false;
} catch (UnsupportedFlavorException e) {
return false;
}

int childIndex = dropLocation.getChildIndex();
if (childIndex == -1) {
childIndex = model.getChildCount(path.getLastPathComponent());
}

DefaultMutableTreeNode newNode = new DefaultMutableTreeNode(transferData);
DefaultMutableTreeNode parentNode = (DefaultMutableTreeNode) path.getLastPathComponent();
model.insertNodeInto(newNode, parentNode, childIndex);

TreePath newPath = path.pathByAddingChild(newNode);
tree.makeVisible(newPath);
tree.scrollRectToVisible(tree.getPathBounds(newPath));
return true;
}
});

JScrollPane pane = new JScrollPane(tree);
f.add(pane, BorderLayout.CENTER);

tree.setDropMode(DropMode.USE_SELECTION);
f.setSize(300, 400);
f.setVisible(true);
}
}