試題詳解

34. HashMap props = new HashMap()； 

35. props.put("key45", "some value")； 

36. props.put("keyl2", "some other value")； 

37. props.put("key39", "yet another value")；

 38. Set s = props.keySet()； 

39. //insert code here 

What inserted at line 39, will sort the keys in the props HashMap?
(A) Arrays.sort(s)；
(B) s = new TreeSet(s)；
(C) Collections.sort(s)；
(D) s = new SortedSet(s)；