The method DateTimeFormatterBuilder.appendOffset(String,String) can throw an exception that is not properly specified. The current spec implies an exception as follows: "The format of the offset is controlled by a pattern which must be one of the following", however there is no @throws clause.

Fix proposed as follows:

     * @param pattern the pattern to use, not null
     * @param noOffsetText the text to use when the offset is zero, not null
     * @return this, for chaining, not null
     * @throws IllegalArgumentException if the pattern is invalid
     */
    public DateTimeFormatterBuilder appendOffset(String pattern, String noOffsetText) {

(around line 914)