interface Algebra { int operate(int a, int b); } enum Operation { ADD, SUB, MUL, DIV } 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) { case ADD: 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(); } } }