9 - Inheritance

Question 1

Inheritance

Answer 1

is the process of deriving a new class from an existing one

Question 2

One purpose of inheritance is …

Answer 2

to reuse existing software

Question 3

Inheritance creates an …

Answer 3

is-a relationship between the parent and child classes.

Question 4

Extends

Answer 4

Java keyword to indicate that a new class is being derived from an existing class.

Question 5

Protected

Answer 5

allows derived classes to reference it. Provides encapsulation that permits inheritance.

Question 6

Super

Answer 6

used in a class to refer to its parent class such as a class’s constructor.

Question 7

single inheritance

Answer 7

Java’s approach to inheritance is called single inheritance, meaning a derived class can only have one parent.

Question 8

A child class can override(redefine) …

Answer 8

the parent’s definition of an inherited method. Must have the same name and same signature.

Question 9

Shadow variable

Answer 9

if a variable of the same name is declared in a child class.

Question 10

class hierarchy

Answer 10

A child of one class can be the parent of one or more other classes

Question 11

Common features should be located as high …

Answer 11

in a class hierarchy as is reasonable possible.

Question 12

Object class

Answer 12

All Java classes are derived, directly or indirectly, from the Object class.

Question 13

What methods are inherited by every class in a Java program?

Answer 13

toString

equals

Question 14

An abstract class cannot …

Answer 14

be instantiated. It represents a concept on which other classes can build their definitions. They are like placeholders for all derived classes.

Question 15

Abstract children and parent relationship…

Answer 15

A class derived from an abstract parent must override all of its parent’s abstract methods, or the derived class will also be considered abstract.

Question 16

Inheritance can be applied to interfaces …

Answer 16

so that one interface can be derived from another.

Question 17

Private members are inherited by the child class…

Answer 17

but cannot be referenced directly by name. They may be used indirectly, however.

Question 18

Inheritance: Every derivation should be an …

Answer 18

is-a relationship. The child should be a more specific version of the parent.

Question 19

Inheritance: Design a class hierarchy to capitalize…

Answer 19

on reuse and potential reuse in the future.

Question 20

Inheritance: Push _______ as high in the class hierarchy as possible.

Answer 20

common features

Question 21

Inheritance: Override methods as appropriate….

Answer 21

to tailor or change the functionality of a child.

Question 22

Inheritance: Add new variables to the child class as needed but dont….

Answer 22

shadow(redefine) an inherited variable.

Question 23

Inheritance: allow each class to…..

Answer 23

manage its own data. Therefore, use the super reference to invoke a parent’s construction and to call overridden versions of methods if appropriate.

Question 24

Inheritance: Use interfaces to…

Answer 24

create a class that serves multiple roles (simulating multiple inheritance).

Question 25

Inheritance: override general methods such as…

Answer 25

toString and equals appropriately in child classes so that the inherited version don’t cause unintentional problems later.

Question 26

Inheritance: Use visibility modifiers carefully to …

Answer 26

provide the needed access in derived classes without violating encapsulation.

Question 27

final

Answer 27

keyword that can be used to restrict in heritance and prevents it from being overridden in other classes.