10 Reusing implementations through Inheritance
| Exam objectives covered in this chapter |
What you need to know |
| [9.1] Create and use subclasses and superclasses |
Why and how to extend classes. Where and how to use parent and child classes. |
| [9.2] Create and extend abstract classes |
How to define abstract classes – with or without abstract methods. How to extend abstract classes, creating concrete or abstract classes. |
| [9.3] Enable polymorphism by overriding methods |
When to override implementations of base classes. How to define polymorphic or overridden methods. |
| [9.4] Utilize polymorphism to cast and call methods, differentiating object type versus reference type |
How to determine the valid types of the variables that can be used to refer to an object. How to determine the differences in the members of an object, which ones are accessible, and when an object is referred to using a variable of an inherited base class or an implemented interface. |
| [9.5] Distinguish overloading, overriding, and hiding |
The rules to spot method overloading, overriding and hiding. |
10.1 Inheritance with classes
10.1.1 The need to inherit classes
10.1.2 Benefits
10.1.3 A derived class contains within it an object of its base class
10.1.4 Which base class members are inherited by a derived class?
10.1.5 Which base class members aren’t inherited by a derived class?
10.1.6 Derived classes can define additional properties and behaviors
10.2 Abstract classes
10.2.1 Defining an abstract class
10.2.2 abstract methods
10.2.3 Extending an abstract class
10.2.4 Abstract base class versus concrete base class
10.3 Enable polymorphism by overriding methods
10.3.1 Polymorphism with classes
10.3.2 Binding of variables and methods at compile time and runtime
10.3.3 Polymorphism with interfaces
10.4 Reference variable and object types
10.4.1 Using a variable of the derived class to access its own object
10.4.2 Using a variable of a superclass to access an object of a derived class
10.4.3 Using a variable of an implemented interface to access a derived class object
10.4.4 Binding of variables and methods at compile time and runtime
10.4.5 The need for accessing an object using the variables of its base class or implemented interfaces
10.5 Casting
10.5.1 How to cast a variable to another type
10.5.2 Need for casting
10.6 Use this and super to access objects and constructors
10.6.1 Object reference: this
10.6.2 Object reference: super