How to achieve polymorphisim using composition

Question

How to achieve polymorphisim using composition

Answer 1

Not possible. This is very wrong, polymorphism is very much facilitated by Composition (or Aggregation).
Polymorphism goes hand in hand with
either imlementing an interface or extending a class.The fundamental objective of Polymorphism is the handling/using Objects of multiple types in a uniform manner, i.e. to a fixed contract.
Composition may be used to delegate the
implementation of an interface or subclass' method.Composition allows much more than delegation, it about defining a static contract between two objects.
composition itself is not polymorphic.The main difference between simple composition and polymorphism is the valence. In Polymorphism it is explicityly 1. .N in the case of composition it is implicitly 0..N
I think this code proves that a Composition of classes for Odd and Even can be used polymorphically.
public class Polymorphism {
  abstract public class Base {
    public void method()
      System.out.println( this.getClass().getName() + ".method()" ) ;
  public class Odd extends Base {
  public class Even extends Base {
  final int ARRAY_SIZE = 10;
  Base[] composition = new Base[ARRAY_SIZE] ;
  public Polymorphism() {
    for(int i = 0 ; i < ARRAY_SIZE ; i+=2 )
      composition[i] = new Even() ;
      composition[i+1] = new Odd() ;
  public void process() {
    for(int i = 0 ; i < ARRAY_SIZE ; i++ ) {
      composition.method() ;
public static void main(String[] args) {
Polymorphism polymorphism = new Polymorphism();
polymorphism.process() ;