import java.util.Arrays; public class Demo5 { public static void main(String[] args) { NonComparable[] a = new NonComparable[3]; a[0] = new NonComparable(true); a[1] = new NonComparable(false); a[2] = new NonComparable(false); System.out.println( Arrays.toString(a) ); exch(a, 0, 2); System.out.println( Arrays.toString(a) ); } private static void exch( T[] a, int i, int j ) { T help; help = a[i]; a[i] = a[j]; a[j] = help; } }