Could you comment on my little program? What design pattern it is?

Hi,

I am amazed at the following way transforming a Class into different
Class on the fly(Expert becomes Singer, Chef or Painter). Could you
throw in some comment for me? Is this called Strategy design pattern?

Now I do feel "has-a" is more powerful than "is-a".

Thank you very much.

<code>

interface Talent
{
    void showTalent();
}

class Singing implements Talent
{
    public void showTalent()
    {
        System.out.println("do-rei-mei");
    }
}

class Painting implements Talent
{
    public void showTalent()
    {
        System.out.println("yellow, blue, red");
    }
}

class Cooking implements Talent
{
    public void showTalent()
    {
        System.out.println("gong-bao chicken");
    }
}

//Skills of Expert is undecided right now. His skills will be set on the
fly. I am truely amazed at how powerful this technique it is.
public class Expert {
    private Talent myTalent = null; //undecided yet

    public Expert(Talent t)
    {
        myTalent = t;
    }

    public void serve()
    {
        myTalent.showTalent();
    }

    public static void main(String[] args)
    {
        Expert anExpert = new Expert(new Singing()); //this expert is singer
        anExpert.serve();

        anExpert = new Expert(new Cooking()); //this expert is Chef
        anExpert.serve();

        anExpert = new Expert(new Painting()); //this expert is Painter
        anExpert.serve();
    }
}
</code>