Content types Collections can hold either objects or primitive C types. All contents of a collection must be of the same type. You declare which type the collection will hold at collection initialization time, and the type can not be changed later.
Many operations are independent of the type the collection holds.
Other operations need to take arguments of different types depending on whether the contents are objects or some other type. In this case there will be two methods, distinguished by the words Object and Element in their method name.