swt controls里的控件list

swt controls里的控件list，怎么显示滚动条，并且滚动条自动移动到最下边时，显示最新内容

 package com.jokul;

 import org.eclipse.swt.widgets.Display;
 import org.eclipse.swt.widgets.Shell;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.widgets.Label;
 import org.eclipse.swt.widgets.List;
 import org.eclipse.swt.widgets.ScrollBar;

 public class ListTest {

     protected Shell shell;
     protected static List list;

     /**
      * Launch the application.
      * @param args
      */
     public static void main(String[] args) {
         try {
             ListTest window = new ListTest();
             window.open();
         } catch (Exception e) {
             e.printStackTrace();
         }
     }

     /**
      * Open the window.
      */
     public void open() {
         Display display = Display.getDefault();
         createContents();
         shell.open();
         shell.layout();
         while (!shell.isDisposed()) {
             if (!display.readAndDispatch()) {
                 display.sleep();
             }
         }
     }

     /**
      * Create contents of the window.
      */
     protected void createContents() {
         shell = new Shell();
         shell.setSize(450, 300);
         shell.setText("SWT Application");

         list = new List(shell, SWT.BORDER | SWT.V_SCROLL);
         list.setItems(new String[] {});
         list.setBounds(10, 35, 414, 217);

         Label label = new Label(shell, SWT.NONE);
         label.setBounds(10, 10, 343, 17);
         label.setText("\u6F14\u793A\u6EDA\u52A8\u6761\u600E\u4E48\u79FB\u52A8\u5230\u6700\u4E0B\u8FB9\u7684");

         for(int i = 0; i < 100; i++) {
             showInList("info:" + i);
         }
     }

     /**
      * 在swt的list上显示信息
      * @param str
      */
     private static void showInList(final String str){
         Display.getDefault().asyncExec(new Runnable() {
             public void run() {
                 list.add(str);

                 int count = list.getItemCount();
                 list.setSelection(count - 1);

                 ScrollBar sb = list.getVerticalBar();
                 if(sb !=null && sb.isVisible()) {
                     sb.setSelection(sb.getMaximum());
                 }
             }
         });

     }
 }