Retain Cycles: Why is that such a bad thing?

Question

There are two Objects A and B. A creates B and retains it. B has an instance variable that points to A, retaining it. So both retain eachother. Some people say, that this st

Answer 1

The problem is this: A points to and retains B, and B points to and retains A. When there are no other references to A or B, there will be no way to release them, because you app doesn't have any references to them at that point. This is called a reference cycle, and it a type of memory leak common in any reference counted system. The way this is solved in most high level languages is by using garbage collection rather than reference counting.