For an array Based Implementation of Lists with Dynamic Allocation, why we should define a destructor by ourselves and what the destructor will do?

How can the performance of an ArrayList be evaluated?

Assume class MyStack implements the following StackGen interface. For this question, make no assumptions about the implementation of MyStack except that the following interface methods are implemented and work as documented. Write a public instance method for MyStack, called interchange(T element) to replace the bottom "two" items in the stack with element. If there are fewer than two items on the stack, upon return the stack should contain exactly two items that are element.

Compare the operations of ArrayLists and Linked Lists? What are the similarities and differences of both forms?