hashmap

1.     Iterator iter = map.values().iterator();  
2.     while(iter.hasNext())  
3.     {  
4.         ArrayList<String> item = (ArrayList<String>)iter.next();  
5.         if(item.size()>1)  
6.             res.addAll(item);  
7.     } 
8. http://blog.csdn.net/linhuanmars/article/details/21664747