gistfile1.java

public class Main {
    public static void main(String[] args) {
        Set<Integer> set = new TreeSet<Integer>(new Comparator<Integer>() {
            @Override
            public int compare(final Integer o1, final Integer o2) {
                return 0;
            }
        });

        set.add(1); set.add(2); set.add(1);

        for (Integer integer : set) {
            System.out.println(integer);
        }
    }
}