CIS191-S09/Slides and Notes/March 16 - 20

From MCIS Wiki

Abstract Classes and Methods

• Why would you make a class abstract?
• How do you make a class abstract?
• Why would you make a method abstract?
• How are abstract methods different from ordinary ones?
• What does an abstract method lack?
• What does “concrete” mean?

The Object class

• What is “Object”?
• Why would you declare a variable as Object?
• How can you get something out of the Object class?
• What are the methods in Object?
• How do you avoid using Object?

Interfaces

• How does an interface relate to a class?
• How do you declare an interface?
• How are interfaces different from classes?
• Do you have to say “implements” if you happen to have the methods associated with an interface?
• Does an interface have a constructor?
• Can one interface extend another?