ConcurrentHashMap occur value is null while values().iterator iterating

Question

 ConcurrentHashMap map=buildMap();//init data
  Iterator<Object> iterator=map.values().iterator();
  while(iterator.hasNext()){
      Objetc data=iterator.next();//(1)
      System.out.println(data);
  }

can other Thread do something then make the (1)data is null?if can ,then how to do??

Answer 1

否ConcurrentHashMap不允许将null作为键或值。