Creating Generics Classes

Often the classes we create deal with specific types; for example, a Book may have title of type String and a list of Authors, a Publisher, and so on. Sometimes though, especially when working with collections, we may not want to tie the members of a class to specific types. For example, a list of Books vs. a list of Authors are both lists. The list should be general enough to support members of either of those types, or other types, but specific enough to disallow, for example, adding an Author to a list of Books. Generics classes are used ...