Need help with java program

Directions

Write a recursive function called sumDigits with the following signature:

public static long sumDigits(long n)

that computes the sum of the digits in a number repeatedly, until the sum is a single digit.

For example, if we call sumDigits(123456), the following would result:

sumDigits(123456) => 1+2+3+4+5+6 => 21 => 2+1 => 3

so the final answer would be 3.

You must meaningfully use recursion for this lab in order to receive any credit.

Hint: For this problem it might be useful to convert back and forth between longs and strings. This can be done using the Long.parseLong method and the Long.toString method.