Midterm Exam #1 Topics

The exam is open book and open notes and you are free to use a calculator or whatever other computing devices you feel may aid you, but it is not open-neighbor. You can use a computing device and the Internet to access Blackboard/online books/notes/course website, but not to compile/run programs or to communicate with others online.

Inheritance

• Why use inheritance, how it helps you
• What is inherited (e.g. public, protected)
• public vs. protected vs. private
• Terminology (e.g. derived, base, super, child, sub)
• Invoking super, calling something in the base class
• Overriding a method - must have same signature or overloading happens

Polymorphism

• Idea of overriding a method and the method invoked is based on the object at the time it is created, not the data type of the object
• How polymorphism helps your programs be extensible
• Given a program with some inheritance hierarchy, determine which methods are invoked or could be invoked (some using polymorphism, others not)
• How to define the toString method
• How to define the equals method, including checking object type, how this is used in methods like .contains()

Abstract Classes/Methods

• What is an abstract method? An abstract class?
• Why to make a class abstract
• Why we can't make an instance of an abstract class
• Misconception: can have code in an abstract classes

Interfaces

• Comparison to abstract class
• Multiple interfaces
• Using the Comparable interface
• How this is used in libraries such as Array.sort

Cloning

• Shallow vs. deep copy and problem with references
• Using the cloneable interface and implementing clone()
• Idea of a marker interface, using super.clone()

UML

• Be able to write a class diagram
• Be able to write a sequence, use case, activity, or state transition diagram

Class Design

• Be able to design classes with the proper responsibilities
• has-a vs. is-a relationship to other classes