Java Code:
import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Tree;
import org.eclipse.swt.widgets.TreeItem;

/**
 * @author Steven Holzner
 * 
 * To change the template for this generated type comment go to
 * Window>Preferences>Java>Code Generation>Code and Comments
 */

public class SWTTrees {

  public static void main(String[] args) {
    Display display = new Display();
    Shell shell = new Shell(display);
    shell.setText("Trees");

    final Tree tree = new Tree(shell, SWT.BORDER);
    tree.setSize(290, 290);
    shell.setSize(300, 300);

    for (int loopIndex1 = 0; loopIndex1 < 5; loopIndex1++) {
      TreeItem item0 = new TreeItem(tree, 0);
      item0.setText("Level 0 Item " + loopIndex1);
      for (int loopIndex2 = 0; loopIndex2 < 5; loopIndex2++) {
        TreeItem item1 = new TreeItem(item0, 0);
        item1.setText("Level 1 Item " + loopIndex2);
        for (int loopIndex3 = 0; loopIndex3 < 5; loopIndex3++) {
          TreeItem item2 = new TreeItem(item1, 0);
          item2.setText("Level 2 Item " + loopIndex3);
        }
      }
    }

    shell.open();
    while (!shell.isDisposed()) {      if (!display.readAndDispatch())
        display.sleep();
    }
    display.dispose();
  }
}