Double base palindromes

package euler;

public class Problem_036 {

    public static void main(String[] args) {
        long startTime = System.currentTimeMillis();

        System.out.println(doubleBasePalindromSum(1000000));

        long endTime = System.currentTimeMillis();
        System.out.println("It took " + (endTime - startTime) + " ms.");
    }

    private static int doubleBasePalindromSum(int upperbound) {
        int sum = 0;

        for(int i = 1; i < upperbound; i++) {
            if(isPalindrome(Integer.toString(i)) && isPalindrome(Integer.toBinaryString(i))) {
                sum += i;
            }
        }

        return sum;
    }

    private static boolean isPalindrome(String num) {
        String numStr = num;
        StringBuilder reverse = new StringBuilder(numStr).reverse();
        return numStr.equals(reverse.toString());
    }
}