This is for programming with java. Please help

Consider the following recursive method. private static void mystery (int num) if (num > O) mystery (num / 2); System.out.print (num % 2); (a) What would be the output of the call mystery (25)? Show a tree diagram with all recursive calls. (6 points) (b) Rewrite the body of this method so that it produces the exact same output using a while loop instead of recursion. (2 points) (c) What exactly is the purpose of this mystery method? (2 points)