Recursion in Java: I'm having a problem with printing the result

Question

Down below is my code. My problem is that if I try to use the method on an array I get an ArrayIndexOutOfBounds Exception and I have no idea why. Maybe someone can help.

public class Recursion {
    
        public static void main(String[] args) {
            
            int[] array = new int[] {3, 4, 7, 2, 6};
            stepSum(array);
            
        }
        
        public static void stepSum(int[] numbers) {
            if(numbers.length == 0) {
                return;
            } else if (numbers.length == 1) {
                System.out.println(numbers[0]);
            } else {
            int[] sumNumbers = new int[numbers.length - 1];
            for (int i = 0; i < numbers.length; i++) {
                sumNumbers[i] = numbers[i] + numbers[i+1];
            }
            stepSum(sumNumbers);
            }
            
            for (int number : numbers) {
                System.out.print(number + " ");
            }
            System.out.println();
            
        }
        
    }

Answer 1

numbers[i+1]

That is going to exceed the index the last time through the loop because i is the last valid index.

Answer 2

In your for loop replace numbers.length with sumNumbers.length

Because numbers.length is larger than the new sumNumbers.length it will end up always doing one iteration more than the sumNumbers.length. This won't work.