Unnamed

import java.util.*;


public class TestingComparable
{

    public static void main ( String[] args )
    {
        new TestingComparable().run();
    }



    void run ()
    {
        List<X> list = new ArrayList<X>();

        list.add( new X(1) );
        list.add( new X(3) );
        list.add( new X(2) );

        printList( list );

        Collections.sort( list );

        printList( list );

    }



    void printList ( List<X> list )
    {
        for ( X x : list ) {
            System.out.print( x.n+" " );
        }
        System.out.println();
    }



    class X implements Comparable<X>
    {
        private int n;

        public X ( int n )
        {
            this.n = n;
        }

        public int compareTo ( X o )
        {
            return n - o.n;
        }
    }

}