code: public static Integer parse(String str) throws NumberFormatException {
  
          // Return null if no value provided
          if (str == null || str.isEmpty())
              return null;
  
          // Parse as integer
          return Integer.valueOf(str);
  
      }
docs: Parses the given string as an integer, where the given string is in the
  format required by a numeric field.
  
  @param str
  The string to parse as an integer, which may be null.
  
  @return
  The integer representation of the given string, or null if the given
  string was null.
  
  @throws NumberFormatException
  If the given string is not in a parseable format.