How do you fake call by reference in Java, or more precisely, how can a callee influence the values of it’s caller’s variables?

• Use a holder/wrapper object passed to the callee as a parameter. The callee can change the object’s fields. That object may be as simple as an Object[]. In Java, a callee may change the fields of a caller’s object passed as a parameter, but not the caller’s reference to that object. It can’t make the caller’s variable passed as a parameter point to a different object. It can only make its local copy point to a different object. A holder class is just a class with fields to hold your values. It has no methods other than accessors for the fields.
• Have the callee return the new values, perhaps wrapped in an holder class or Object[], and have the caller store them away somewhere.
• Communicate via a static or instance variable visible to both caller and callee.
• Use a delegate object. The callee calls its methods to save the results for the caller.