Two approaches used to write the specifications for operations between a sender and a receiver object (e.g., Queue) are based on design by contract and defensive design.

1. Write test cases that satisfies the all transitions criteria for the Queue using the state machine. Note one test case should cover one transition. Assume the Queue stores Integer objects with maximum size of 5 objects.
2. Using the Eclipse IDE write well documented code for two (2) Queue classes, one for design by contract (QueueDC) and the other for defensive design (QueueDD). Assume the Queue stores Integer objects with maximum size of 5 objects.