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("u6F14u793Au6EDAu52A8u6761u600Eu4E48u79FBu52A8u5230u6700u4E0Bu8FB9u7684");

        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());
                }
            }
        });
        
    }
}