code: public static boolean isFloatNoExponent(String str)
      {
          int len = str.length();
          if (len == 0)
          {
              return false;
          }
  
          // skip first char if sign char
          char c = str.charAt(0);
          int  i = ((c == '-') || (c == '+')) ? 1 : 0;
  
          // is it only a sign?
          if (i >= len)
          {
              return false;
          }
  
          boolean decimalPointFound = false;
  
          do
          {
              c = str.charAt(i);
              if (c == '.')
              {
                  // is this a second dot?
                  if (decimalPointFound)
                  {
                      return false;
                  }
  
                  decimalPointFound = true;
              }
              else if (!Character.isDigit(c))
              {
                  return false;
              }
  
              i++;
          }
          while (i < len);
  
          return true;
      }
docs: Checks that the string represents a floating point number that CANNOT be
  in exponential notation
  
  @param str the string to check
  
  @return boolean