How to find the greatest common divisor of two integers in java?

This was another coding challenge I came across while practising online. Little bit tricky, however, I found a solution (I say 'a' solution because there can be alternative ways to do the same) for it. 

So, what are we suppose to do here?

• A method accepts two integer parameters and we need to find the highest divisible integer by which both the numbers could be divided without a remainder.
• If either one of the given number is less than 10 then the method should return -10 indicating invalid input.

here is my solution and I hope it's helpful.

public class GreatestCommonDivisor {
    public static int getGreatestCommonDivisor(int first, int second){
        int greatestCommonDivisor = -1;

        if(first >= 10 && second >= 10){
            int smallerNumber = first < second ? first : second;

            for(int i = smallerNumber ; i >= 1 ; i--){
                if( (first % i == 0) && (second % i == 0)){
                    greatestCommonDivisor = i;
                    break;
                }else{
                    continue;
                }
            }
        }
        return greatestCommonDivisor;
    }
}