An interesting Recursion Problem

While I was refreshing some of my java concepts I came across this site with an interesting problem to be solved using recursion. To brush up i quickly wrote three basic programs, viz, sum to given input, product to given input and value of 2^(given number).

Here's the problem statement:

Write a method that accepts an integer parameter n and returns a string of stars (asterisks) 2ⁿ long (i.e., 2 to the n^th power).
For example:

Call	Output	Reason
stringRec(0);	"*"	20 = 1
stringRec(1);	"**"	21 = 2
stringRec(2);	"****"	22 = 4
stringRec(3);	"********"	23 = 8
stringRec(4);	"****************"	24 = 16

Here is what I came up with:

private static void stringRec(int i) {     if (i == -1) {         System.out.print("*");     }     else {         for (int j = i; j >= 0; j--) {             stringRec(j - 1);         }     } }