单例模式

package moder;

public class Huandi
{
private static final Huandi hd=new Huandi();
private Huandi(){};
public static Huandi getHuandi(){
return hd;

}
public void say()
{
System.out.println("我是huandi");
}
}
////////////////////////////////////////////////////////////////
package moder;

public class Single
{
        private static Single single=null;
        private Single(){};
        public static synchronized Single getSingle()
        {
        if(single==null)
             {
             single=new Single();
                 }
        return single;
        }
        public void say()
        {
        System.out.println("wo shi single");
        }
       
      
}