Functional Interfaces in Java

Create a Java program to demonstrate the use of a functional interface with a single abstract method

Calculator is a functional interface defined with the @FunctionalInterface annotation, indicating that it has exactly one abstract method.
Two lambda expressions are used to provide implementations for the calculate method of the Calculator interface: one for addition and one for subtraction.
In the main method, instances of the Calculator interface are created using lambda expressions.
These instances are then used to perform addition and subtraction operations, demonstrating the use of lambda expressions to provide behavior to functional interfaces.

Source Code

@FunctionalInterface
interface Calculator
{
	int calculate(int a, int b);
}
 
public class Main
{
	public static void main(String[] args)
	{
		Calculator addition = (a, b) -> a + b;
		Calculator subtraction = (a, b) -> a - b;
 
		System.out.println("Addition : " + addition.calculate(5, 7));
		System.out.println("Subtraction : " + subtraction.calculate(10, 4));
	}
}

Output

Addition : 12
Subtraction : 6

Functional Interfaces in Java

Source Code

Output

Example Programs

Interface Programs in Java