Homework Create your own class with an internal collection of a different class. It should have methods for count, add, isFull etc. Remember to write tests for your classes!
Some examples:
A Bus class with an array, passengers of Persons. A Classroom class with an array, students of Persons. A Library class with an array, stock, of Books. Extensions:
Add a third class which interacts with the other two. E.g. you could add a BusStop with a method that takes a Bus and moves Persons from the BusStop to the Bus.