How to write Composition and Aggregation in java

Question

I want to know how to identify composition and aggregation code in java. I have C++ Code, But I don't understand how to write in java.

Composition

class A {};
class B { A composited_A; };

Aggregation via Pointer

class A {};
class B
{
A* pointer_to_A;
B(A anA){ 
pointer_to_A = &anA;
}

Can anyone please tell me how both are working in JAVA. (I know what is meant by Composition and aggregation ) };

Answer 1

Java itself simply does not make the distinction between composition and aggregation. You cannot express the idea of ownership of a reference in the Java type system – if you explicitly need to express ownership you must denote this with some other means (usually simply by constructing a new object to be stored in the instance of a class).

Since Java has a GC, ownership for memory doesn’t need to be expressed at all; memory is owned and managed solely by the GC. Of course, the same is not true for other resources and here you might still want to express ownership.