[Java] Is there a solution to the cross-reference between the two classes?

To refer to the methods that two classes need each other

Creating each class object with each other results in an error due to cross-referencing...

Variables do not create class objects and do not interfere with cross-class references.

Obviously, stack overflow errors occur in situations where the methods are referenced to each other.

Is there a way to solve this problem other than creating a separate class that mediates the two classes?