Compare inheritance and composition, the two fundamental ways to relate Java classes, then practice debugging ClassCastExceptions in Java inheritance.

Learn the four types of polymorphism in Java, then start using subtype polymorphism to execute different forms of the same Java method.

Today, C++, C#, Java, Visual Basic.NET and Python are popular object-oriented languages. The following compares basic OOP terms with traditional programming. See object-oriented DBMS.