LAB 5

Question 1

is an important feature of object-oriented programming in Java. It allows for one class (child class) to inherit the fields and methods of another class (parent class). For instance, we might want a child class Dog to inherent traits from a more general parent class Animal.

Answer 1

Inheritance

Question 2

In simple Java programs, you may work with just one class and one file. However, as your programs become more complex you will work with multiple classes, each of which requires its own file. Only one of these files in the Java package requires a ______ method, and this is the file that will be run in the package.

Answer 2

main()

Question 3

For example, say we have two files in our Java package for two different classes:

Shape, the is the ______ class
Square, the ______ class.

Answer 3

parent class.
child class.

Question 4

In Java, a child class inherits its parent’s fields and methods, meaning it also inherits the parent’s constructor. Sometimes we may want to modify the constructor, in which case we can use the _____ method, which acts like the parent constructor inside the child class constructor.

Answer 4

super() method

Question 5

keeps a parent class member accessible to its child classes, to files within its own package, and by subclasses of this class in another package.

Answer 5

protected

Question 6

Adding ____ before a parent class method’s access modifier makes it so that any child classes cannot modify that method - it is immutable.

Answer 6

final

Question 7

Java incorporates the object-oriented programming principle of ____

_______ allows a child class to share the information and behavior of its parent class while also incorporating its own functionality. This allows for the benefits of simplified syntax and reduced cognitive overload for developers.

Answer 7

polymorphism.

Question 8

In Java, we can easily ______ parent class methods in a child class.

______ a method is useful when we want our child class method to have the same name as a parent class method but behave a bit differently.

Answer 8

override / overriding

Question 9

In order to override a parent class method in a child class, we need to make sure that the child class method has the following in common with its parent class method:

Answer 9

-Method name
-Return type
-Number and type of parameters

Question 10

In Java, polymorphism allows us to put instances of different classes that share a parent class together in an __________

For example, if we have an Animal parent class with child classes Cat, Dog, and Pig we can set up an ____ with instances of each animal and then iterate through the list of animals to perform the same action on each.

Answer 10

array or ArrayList.

Question 11

is when a child class inherits from a parent class.

Answer 11

Single Inheritance

Question 12

is when a child class inherits from a parent class which in turn inherits from another parent class.

Answer 12

Multilevel Inheritance

Question 13

is when a child class inherits from a parent class and there is another sibling class that also inherits from the same parent class.

Answer 13

Hierarchical Inheritance

Question 14

are reusable pieces of code in classes.

Answer 14

Methods

Question 15

The difference between a method and a function is that

Answer 15

methods are always related to a class or an object

Question 16

Methods consist of at least the following elements:

Answer 16

Return type: The type of the value that is returned from the method

Name: The name of the method

Question 17

The ____ of a method should describe as much as possible what the method is doing.

Answer 17

Name

Question 18

is described by a data type and a name.

can be used to access the value inside the method body. A method without any ______ must have empty parenthesis () after the method name.

Answer 18

Parameters

Question 19

can change how a method is allowed to be called (public, protected, private, package private), if the method is working on object state or should be executable without creating an object out of a class (static), or if the method is allowed to be replaced by inherited classes (final).

Answer 19

Modifier

Question 20

(4) Visibility Modifiers

Answer 20

public
private
package private
protected

Question 21

Methods declared as ____ can be called from everywhere, inside and outside of the object or the class.

Answer 21

public

Question 22

Methods declared as _____ can only be called from inside the object or the class.

Answer 22

private

Question 23

Methods declared as ______ can only be called from classes within the same package.

Answer 23

package private

Question 24

Methods declared as _______ can only be called from inside the class or from inside classes inherited from that class.

Answer 24

protected

Question 25

the ___ keyword prevents methods from being overwritten in inherited classes. It can be combined with other modifiers.

Answer 25

final

Question 26

Methods can throw ______. An example of this is trying to access a file that doesn’t exist.

Answer 26

Exceptions

Question 27

Everything between { and } is called the ________ The ______ contains the actual code, statements, or logic that is executed when the method is called.

Answer 27

body of the method. Body

Question 28

Static methods and variables are declared as static by using the _____ keyword upon declaration.

Answer 28

static

Question 29

are associated with the class as a whole, not objects of the class. Both are used by using the name of the class followed by the . operator.

Answer 29

Static Methods and Variables

Question 30

Static methods cannot access or change the values of

Answer 30

instance variables.

Question 31

Both non-static and static methods can access or change the values of

Answer 31

static variables.

Question 32

In Java, the keywords _____ and _____ define the access of classes, instance variables, constructors, and methods.

Answer 32

public and private

Question 33

restricts access to only the class that declared the structure, while

Answer 33

private

Question 34

allows for access from any class.

Answer 34

public

Question 35

is a technique used to keep implementation details hidden from other classes. Its aim is to create small bundles of logic.

Answer 35

Encapsulation

Question 36

In Java, instance variables are encapsulated by using the ____ keyword. This prevents other classes from directly accessing these variables.

Answer 36

private

Question 37

In Java, _____ return the value of a private variable. This gives other classes access to that value stored in that variable. without having direct access to the variable itself.

Answer 37

accessor methods

Question 38

In Java, ______ reset the value of a private variable. This gives other classes the ability to modify the value stored in that variable without having direct access to the variable itself.

Answer 38

mutator methods

Question 39

take one parameter whose type matches the type of the variable it is modifying. these methods usually don’t return anything.

Answer 39

Mutator methods