code: @NullSafe
    public static String toLowerCase(String value) {
      return value != null ? value.toLowerCase() : null;
    }
docs: Converts the String value to all lower case characters.  toLowerCase is a null-safe operation.
  
  @param value the String value who's characters are all converted to lower case.
  @return the String value with all lower case characters.
  @see #toUpperCase(String)
  @see java.lang.String#toLowerCase()