Question (class relationships)

[Andrei Mura]

Hi!
I have this:
1.

public class A{
	private B b = new B();

	public B getB() {
		return b;
	}
}

What kind of relationship is between object of A class and its contained object b?
I think that is aggregation. Is it right? (Why not?)
2.
Second example:

public class C {
	D d;
	public void setD(D d) {
		this.d = d;
	}
}

I think that is also aggregation, but in some exam's questions i saw that is a direct association.
What's your opinion.

N.B. -2 if i have the same situation but another names, does it change the situation?

 
       public class Car {
	Street street;
	public void setStreet(Street street) {
		this.street = street;
	}
                                    

I'm waiting for your thoughts.
Thanks.