Use Java to write this program

Use each of the concurrency techniques: 1.semaphores 2.message passing

To solve the following concurrency problem:

A parking lot with a capacity of N cars is on an island. A ferry with a capacity of M cars shuttles cars between the mainland and the island. The ferry may cross whenever there are no cars waiting to get on the ferry (even if it is not full) provided that there are cars waiting on the other side. The ferry may also cross whenever it is full or (in the case of crossing to the island) when the number of cars in the ferry would fill the parking lot.