Summary

Clarify the definition of the "Offset O" pattern presentation in java.time.format.DateTimeFormatter class.

Problem

The pattern is based on the CLDR's "Localized GMT format", thus the hour/minute/second digits are omitted if the offset is zero. However the current spec does not clearly mention it, which may confuse the users.

Solution

Clearly mention the zero/non-zero offset cases in the class description.

Specification

Change the "Offset O" section of the class description of java.time.format.DateTimeFormatter class from:

* <b>Offset O</b>: This formats the localized offset based on the number of
* pattern letters. One letter outputs the {@linkplain TextStyle#SHORT short}
* form of the localized offset, which is localized offset text, such as 'GMT',
* with hour without leading zero, optional 2-digit minute and second if
* non-zero, and colon, for example 'GMT+8'. Four letters outputs the
* {@linkplain TextStyle#FULL full} form, which is localized offset text,
* such as 'GMT, with 2-digit hour and minute field, optional second field
* if non-zero, and colon, for example 'GMT+08:00'. Any other count of letters
* throws {@code IllegalArgumentException}.

to:

* <b>Offset O</b>: With a non-zero offset, this formats the localized offset
* based on the number of pattern letters. One letter outputs the
* {@linkplain TextStyle#SHORT short} form of the localized offset, which is
* localized offset text, such as 'GMT', with hour without leading zero, optional
* 2-digit minute and second if non-zero, and colon, for example 'GMT+8'. Four
* letters outputs the {@linkplain TextStyle#FULL full} form, which is localized
* offset text, such as 'GMT, with 2-digit hour and minute field, optional second
* field if non-zero, and colon, for example 'GMT+08:00'. If the offset is zero,
* only localized text is output. Any other count of letters throws
* {@code IllegalArgumentException}.