Multiplying two numbers using Addition operator using Recursion

 public class Multiply{

static int product(int a, int b) {

if (b == 0) {

return 0;

}

if (b > 0) {

return (a + product(a, b - 1));

}

if (b < 0) {

return -product(a, -b);

}

return -1;

}

public static void main(String args[]) {

System.out.println("The multiplication is: " + product(-5, 9));

System.out.println("The multiplication is: " + product(-8, -17));

System.out.println("The multiplication is: " + product(12, 12));

}

}