Default constructor in Java - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a default constructor for the class.

Java

public class Car {
    String model;
    int year;

    public [1]() {
        model = "Unknown";
        year = 0;
    }
}

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

ADefaultConstructor

Bcar

CCar

DCar()

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase class name for constructor

Adding parentheses after the constructor name in the declaration

Using a different name than the class

In Java, the default constructor has the same name as the class and no parameters.

2fill in blank

medium

Complete the code to create an object using the default constructor.

Java

Car myCar = new [1]();

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

Acar

BCar

CMyCar

Dcar()

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase class name

Adding parentheses in the option name

Using a variable name instead of class name

To create an object, use the class name with 'new' and parentheses.

3fill in blank

hard

Fix the error in the constructor declaration.

Java

public class Book {
    String title;

    public [1]() {
        title = "Unknown";
    }
}

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

ABook

BBook()

Cbook

Dvoid Book

Attempts:

3 left

💡 Hint

Common Mistakes

Adding 'void' before constructor name

Using lowercase constructor name

Adding parentheses in the constructor name in declaration

Constructors do not have a return type and must have the same name as the class.

4fill in blank

hard

Fill both blanks to complete the default constructor and initialize the fields.

Java

public class Student {
    String name;
    int age;

    public [1]() {
        name = [2];
        age = 0;
    }
}

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

AStudent

B"Unknown"

C"Default"

Dstudent

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase constructor name

Assigning string without quotes

Using wrong string value

The constructor name must match the class name, and string values must be in quotes.

5fill in blank

hard

Fill all three blanks to complete the class with a default constructor and create an object.

Java

public class Laptop {
    String brand;
    int price;

    public [1]() {
        brand = [2];
        price = [3];
    }
}

Laptop myLaptop = new [4]();

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

ALaptop

B"Generic"

C1000

Dlaptop

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase class name

Missing quotes around string

Using string for price instead of number

Constructor name matches class name, string values use quotes, and price is an integer.