java.lang.ArrayIndexOutOfBoundsException：两个数组的加法为5

Question

我正在编码两个长度相同的数组。但是，当我运行它时，会弹出错误java.lang.ArrayIndexOutOfBoundsException: 5。请您帮忙找出问题所在吗？

public class LongAdditionsDemo {

    private static final int[] A = {2, 4, 9, 2};
    private static final int[] B = {9, 7, 5, 3};

    public static void main(String[] args)
    {
        int[] Sum = new int[A.length + 1];
        Sum = LongAdditionsEqual(A, B);
        System.out.print("The sum is: ");
        for (int k = 0; k < Sum.length; k++)
        {
            System.out.print(Sum[Sum.length - 1]);
        }
    }

    private static int[] LongAdditionsEqual(int[] a, int[] b)
    {
        int[] carry = new int[a.length + 1];
        int[] sum = new int[a.length + 1];

        carry[0] = 0;

        for (int i = 0; i < a.length; i++)
        {
            sum[i] = (a[i] + b[i] + carry[i]) % 10;
            carry[i] = (a[i] + b[i] + carry[i]) / 10;
        }

        sum[a.length + 1] = carry[a.length + 1];

        return sum;
    }
}