Java 获取两个List<String>中不同的数据

public static List<String> getDiffrent(List<String> list1, List<String> list2){           
           Map<String,Integer> map = new HashMap<String,Integer>(list1.size()+list2.size());
           List<String> diff = new ArrayList<String>();
           List<String> maxList = list1;
           List<String> minList = list2;
           if(list2.size()>list1.size()){
               maxList = list2;
               minList = list1;
           }
           
           for (String string : maxList){
              map.put(string, 1);                    
           }
           
           for (String string : minList){
               Integer cc = map.get(string);                    
               if(cc!=null){
                   map.put(string, ++cc);
                   continue;                    
               }           
               map.put(string, 1);                    
           }
           
           for(Map.Entry<String, Integer> entry:map.entrySet()){                    
               if(entry.getValue()==1)                    
               {                    
                   diff.add(entry.getKey());                    
               }                    
           }                               
           return diff;                    
    }

public static void main(String[] args) {
		
		List<String> list1 =new ArrayList<String>();
		for(int i=1;i<10;i++) {
			list1.add(i+"");
			
		}
		
		List<String> list2 =new ArrayList<String>();
		for(int i=5;i<10;i++) {
			list2.add(i+"");		
		}
		List<String> list3 =getDiffrent(list1,list2);
		List<String> list4 =getDiffrent(list2,list1);
		
		System.out.println(list1);
		System.out.println(list2);
		System.out.println("不同值:"+list3);
		System.out.println("不同值:"+list4);
		
	}