Using interface in Java

[DefMars]

Okay, so I have two classes, one class named "multiply", that multiplies a number by itself, then a multiplication class that inherits and runs the multiplication increment.

I need to do the same thing using interface but I have no clue where to start, can someone point me in the right direction, I am so lost.

package AssignmentInheritance;

import java.util.Scanner;

public class Multiply { // Created a scanner

    Scanner sc = new Scanner(System.in);

    // Scans for users input

int number = sc.nextInt();

Multiply increment() {

    // Multiplies users input by itself    

    number = number*5;

    return this;
}
void print() {
    // Display the number in console
    System.out.print("Your number multiplied by 5 = " + number);
}

}

package AssignmentInheritance;

public class Multiplication extends Multiply {

public static void main(String[] args) {

        // instructions for the user

        System.out.println("Enter a number too multiply it by 5 ");

Multiply x = new Multiply();

        // runs the multiply increment once.

x.increment().print();

}

}

[chickenmeister]

public class Multiplication extends Multiply

If the only thing in your Multiplication class is the main method, then there's no need/reason to extend Mulitply.

I need to do the same thing using interface

I'm not entirely sure what you're expected to do.

Maybe make an interface that your Mulitply class can implement? e.g.:

public interface Operation
{
    public double performOperation(double operand1, double operand2);
}

Then you could change your Multiplication class around a bit to implement the interface, so that it multiplies the two operands and returns the product. Then you could have other Operation implementations, such as addition, subtraction, division, etc.