# How to pass a lambda expression as a method parameter in Java?

Java 8Object Oriented ProgrammingProgramming

A lambda expression is an anonymous or unnamed method in Java. It doesn't execute on its own and used to implement methods that are declared in a functional interface. If we want to pass a lambda expression as a method parameter in java, the type of method parameter that receives must be of functional interface type.

## Example

interface Algebra {
int operate(int a, int b);
}
enum Operation {
}
public class LambdaMethodArgTest {
public static void main(String[] args) {
print((a, b) -> a + b, Operation.ADD);
print((a, b) -> a - b, Operation.SUB);
print((a, b) -> a * b, Operation.MUL);
print((a, b) -> a / b, Operation.DIV);
}
static void print(Algebra alg, Operation op) {
switch (op) {
System.out.println("The addition of a and b is: " + alg.operate(40, 20));
break;
case SUB:
System.out.println("The subtraction of a and b is: " + alg.operate(40, 20));
break;
case MUL:
System.out.println("The multiplication of a and b is: " + alg.operate(40, 20));
break;
case DIV:
System.out.println("The division of a and b is: " + alg.operate(40, 20));
break;
default:
throw new AssertionError();
}
}
}

## Output

The addition of a and b is: 60
The subtraction of a and b is: 20
The multiplication of a and b is: 800
The division of a and b is: 2
Published on 19-Dec-2019 13:09:20