isPowerOfTwo

//Given an integer, write a function to determine if it is a power of two.
public class isPowerOfTwo {
    public static boolean isPowerOfTwo(int n) {
        if (n == 1)
            return true;
        else if (n < 0)
            return false;
        else {
            String str = Integer.toBinaryString(n);
            for(int i=1;i<str.length();i++)
            {
                if('1'==str.charAt(i))
                    return false;
            }
        }
        return true;
    }

    public static void main(String[] args) {
      System.out.println(isPowerOfTwo(1024));

    }
}