1. What is the difference between Array and ArrayList? 2. What is the difference between ArrayList and LinkedList? When do you use what? 3. What data structure do you use to implement the Stack? Which one is the effective way of implementation? 4. Caffe problem. You are owning a Caffe and you have 3 machines (Fruit juicer, Sandwich maker and Coffee maker). Each machine can make 4 items at a time. For example, Sandwich maker can make 4 sandwiches at a time, similarly others. Here expectation is that you should utilize the machine to the fullest. Means it is good to prepare 4 items at a time, rather 1 or 2 items. How would you design the system, there by you serve the customer as well as you effectively utilize the machines? NOTE: 12 Noon to 4 PM is the peak time too, that you should NOT make the customer wait for the long time.