Multiple choice technology programming languages

Given: 34. HashMap props = new HashMap(); 35. props.put(”key45”, “some value”); 36. props.put(”key12”, “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?

  1. Arrays.sort(s);

  2. s = new TreeSet(s);

  3. Collections.sort(s);

  4. s = new SortedSet(s);
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

HashMap keys are unordered. Wrapping the keySet in a TreeSet (new TreeSet(s)) automatically sorts elements because TreeSet maintains natural ordering. Arrays.sort() requires arrays, Collections.sort() requires Lists, and SortedSet is an interface.

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