Static methods in interfaces in Java - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a static method in an interface.

Java

public interface Calculator {
    static int [1](int a, int b) {
        return a + b;
    }
}

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

Aadd

Bsum

Ccalculate

Dcompute

Attempts:

3 left

💡 Hint

Common Mistakes

Using a non-descriptive method name.

Forgetting to declare the method as static.

The method name add is used as the static method name in the interface.

2fill in blank

medium

Complete the code to call the static method from the interface.

Java

int result = Calculator.[1](5, 3);

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

Acompute

Badd

Csum

Dcalculate

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to call the method on an instance.

Using a wrong method name.

The static method add is called using the interface name.

3fill in blank

hard

Fix the error in the static method declaration inside the interface.

Java

public interface Printer {
    [1] void print(String message) {
        System.out.println(message);
    }
}

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

Adefault

Bprivate

Cstatic

Dpublic

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'default' instead of 'static'.

Omitting the 'static' keyword.

The method must be declared static to be a static method in an interface.

4fill in blank

hard

Fill both blanks to define and call a static method in an interface.

Java

public interface Utils {
    static String [1](String s) {
        return s.toUpperCase();
    }
}

String result = Utils.[2]("hello");

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

AtoUpperCase

Bconvert

Cuppercase

DmakeUpper

Attempts:

3 left

💡 Hint

Common Mistakes

Using different names in declaration and call.

Using non-descriptive method names.

The static method name toUpperCase is used both in declaration and call.

5fill in blank

hard

Fill all three blanks to create a static method in an interface that returns the square of a number and call it.

Java

public interface MathOps {
    static int [1](int n) {
        return n [2] n;
    }
}

int squared = MathOps.[3](4);

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

Asquare

B*

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using '+' instead of '*' for multiplication.

Using different method names in declaration and call.

The method square multiplies the input by n using the '*' operator and is called as MathOps.square(4).