To answer this question, let's analyze the given code step by step:
TreeSet map = new TreeSet();
map.add("one");
map.add("two");
map.add("three");
map.add("four");
map.add("one");
Iterator it = map.iterator();
while (it.hasNext()) {
System.out.print(it.next() + " ");
}
In this code, a TreeSet named map is created. A TreeSet is a collection that stores elements in a sorted and unique order.
The following elements are added to the map:
- "one"
- "two"
- "three"
- "four"
- "one" (Note that "one" is added again)
Next, an iterator named it is created using the iterator() method of the TreeSet. The iterator allows iterating over the elements in the TreeSet in a sequential manner.
The while loop is then used to iterate over the elements in the TreeSet using the iterator. The condition it.hasNext() checks if there are more elements to iterate over. If there are, the loop continues.
Inside the loop, it.next() is used to retrieve the next element from the TreeSet. This element is then printed using System.out.print().
Let's analyze the output of the code:
- The elements in the
TreeSet are stored in a sorted order.
- Since "four" comes before "one" in alphabetical order, "four" is printed first.
- Next, "one" is printed.
- "three" comes before "two" in alphabetical order, so "three" is printed next.
- Finally, "two" is printed.
Therefore, the output of the code is: "four one three two".
The correct answer is D. "four one three two".