public static void main(String[] args) {

		TreeSet set = new TreeSet();

		set.add("C");

		set.add("B");

		set.add("A");

		set.add("F");

		set.add("D");

		System.out.println(set);

	}

[A, B, C, D, F]

public class TreeSetTest3 {

	public static void main(String[] args) {

		TreeSet<String> set = new TreeSet(new MyComparator() );

		set.add("C");

		set.add("B");

		set.add("A");

		set.add("F");

		set.add("D");

		System.out.println(set);

	}

}

class MyComparator implements Comparator{

	public int compare(Object o1, Object o2) {

		String s1 = (String) o1;

		String s2 = (String) o2;

		return s2.compareTo(s1);

	}

}

public class TreeSetTest2 {

	public static void main(String[] args) {

		TreeSet set= new TreeSet(new Comparator() {

			public int compare(Object o1, Object o2) {

				int i1 = ((Person) o1).score;

				int i2 = ((Person) o2).score;

				return i2 - i1;

			}

		});

		Person p1 = new Person(100);

		Person p2 = new Person(60);

		Person p3 = new Person(70);

		Person p4 = new Person(50);

		set.add(p1);

		set.add(p2);

		set.add(p3);

		set.add(p4);

		System.out.println(set);

	}

}

class Person{

	int score;

	public Person(int score){

		this.score = score;

	}

	@Override

	public String toString() {

		return String.valueOf(this.score);

	}

}

public class CollectionsTest {

	public static void main(String[] args) {

		LinkedList list = new LinkedList();

		list.add(new Integer(5));

		list.add(new Integer(25));

		list.add(new Integer(15));

		list.add(new Integer(35));

		list.add(new Integer(1));

		Comparator r =  Collections.reverseOrder();

		Collections.sort(list, r);

		System.out.println(list);

	}

}