Default JTL timestamp format changed in 2.15.0

[ppkarwasz]

Description

Due to the solution of LOG4J2-3075 all the timestamp patterns are now interpreted as DateTimeFormatter patterns. This caused a change in the interpretation of the default timestamp resolver format "yyyy-MM-dd'T'HH:mm:ss.SSSZZZ" (as noticed in this StackOverflow question):

• before: the timezone pattern ZZZ was printed as -06:00, +00:00 and +06:00,
• after: the timezone pattern ZZZ is printed without the colons: -0600, +0000 and +0600.

Possible solutions

• we can replace the ZZZ format specifier with xxx, which will give exactly the same output as before 2.15.0. The problem with this solution is that there is no FastDateFormat for it,
• we can replace the ZZZ format specifier with XXX. There is a FastDateFormat for it, but it outputs Z for the zero time zone.

Neither of the two solutions corresponds to one of the standard ElasticSearch date formats.