1 public static void HashSetError() {
 2         Map<String, Set<String>> tempMap1 = new HashMap<String, Set<String>>();
 3         for (int i = 0; i < 10; i++) {
 4             Set<String> set = new HashSet<String>();
 5             set.add(String.valueOf(i));
 6             set.add(String.valueOf(i*10));
 7             tempMap1.put(String.valueOf(i), set);
 8         }
 9 
10         Map<String, Set<String>> tempMap2 = new HashMap<String, Set<String>>();
11 
12         Set<String> set = tempMap1.get(String.valueOf(5));
13         tempMap2.put("t", set);
14         
15         for(String str:set){
16             Set<String> tempSet = tempMap2.get("t");
17             tempSet.add(str+"12");            
18         }
19 
20     }