Java tutorial
public class Main { public static void main(String[] args) { // Integer's sum MyCal<Integer> myOwnCalculatorFI = (a, b) -> (a + b); Integer sum = myOwnCalculatorFI.calcIt(5, 5); System.out.println("Sum: " + sum); // String's sum MyCal<String> myOwnCalculatorFI1 = (e, f) -> (e + f); System.out.println("Adder: " + myOwnCalculatorFI1.calcIt("a", "b")); // Double's power MyCal<Double> calculator2 = (a, b) -> (Math.pow(a, b)); System.out.println("Integer's range: " + calculator2.calcIt(2D, 32D)); } } interface MyCal<T> { public T calcIt(T t1, T t2); }