Java Instance return model note!

1. We have a class and define a static method of  getInstance()
 
public class GenDarwinGlobal extends GenDarwinGlobalHelper
{
    /**
     * Script Name   : <b>GenDarwinGlobal</b>
     * Generated     : <b>Mar 31, 2011 1:16:48 AM</b>
     * Description   : Functional Test Script
     * Original Host : WinNT Version 5.2  Build 3790 (S)
     * 
     * @since  2011/03/31
     * @author dwei
     */
    public void testMain(Object[] args) 
    {
        // TODO Insert code here
    }
    public  static GenDarwinGlobal getInstance()
    {
        return new GenDarwinGlobal();
    }
}
 2. Compare these code line, the getInstance sequence will get failed return because it has two new instance belong to different object.

//        FucLib.GenevaFuc.GenDarwinGlobal.getInstance().openBuyTransaction();
    //    FucLib.GenevaFuc.GenDarwinGlobal.getInstance().ClickQuery();
        
        
        FucLib.GenevaFuc.GenDarwinGlobal oGD =  new FucLib.GenevaFuc.GenDarwinGlobal(); 
        oGD.openBuyTransaction();
        oGD.ClickQuery();
3. Also we can using this method to resolve this problem in the instance code .
 

private static GenDarwinGlobal instance = null;
public static synchronized GenDarwinGlobal getInstance()
{
   if( instance == null)
   {
    instance = new GenDarwinGlobal();
   }
    return instance;
}