/** * Main method. * * @param args */ public static void main(String[] args) { Sumator sumator = new Sumator(); String firstNumber = sumator.input(); String secondNumber = sumator.input(); try { System.out.println("Sum of numbers is: " + sumator.calculate(firstNumber, secondNumber)); } catch (NumberFormatException e) { System.out.println("Invalid format. Please enter only digits"); } }