Why object-oriented programming is used in Java - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a class named Car.

Java

public class [1] {}

Drag options to blanks, or click blank then click option'

AObject

Bcar

CCar

DVehicle

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase for class names

Using unrelated names

The class name should start with a capital letter and match the intended object, here 'Car'.

2fill in blank

medium

Complete the code to create an object of class Car.

Java

Car myCar = new [1]();

Drag options to blanks, or click blank then click option'

ACar

BVehicle

Ccar

DObject

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase class names

Using wrong class names

To create an object, use the class name with 'new'. Here, 'Car' matches the class.

3fill in blank

hard

Fix the error in the method to return the car's speed.

Java

public int getSpeed() {
    return [1];
}

Drag options to blanks, or click blank then click option'

Aspeed

Bthis.speed

CSpeed

DgetSpeed

Attempts:

3 left

💡 Hint

Common Mistakes

Using method name instead of variable

Wrong case for variable name

Use 'this.speed' to refer to the instance variable speed inside the method.

4fill in blank

hard

Fill both blanks to define a constructor that sets the car's speed.

Java

public [1](int [2]) {
    this.speed = speed;
}

Drag options to blanks, or click blank then click option'

ACar

Bspeed

CCarSpeed

Dvalue

Attempts:

3 left

💡 Hint

Common Mistakes

Constructor name different from class

Parameter name mismatch

The constructor name must match the class name 'Car'. The parameter name is 'value' to assign to the instance variable 'speed'.

5fill in blank

hard

Fill all three blanks to create a method that increases the car's speed by a given amount.

Java

public void [1](int [2]) {
    this.speed [3] amount;
}

Drag options to blanks, or click blank then click option'

Aaccelerate

Bamount

C+=

DspeedUp

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong method name

Using '=' instead of '+='

Parameter name mismatch

The method name is 'accelerate', parameter is 'amount', and '+=' adds the amount to speed.