java.time.ZonedDateTime.parse and iso8601?

Question

Why does the JDK8 DateTime library seem to not parse valid iso8601 date time strings? It chokes on time zone offsets expressed like "+01" instead of "+01:00"

This works:

java.time.ZonedDateTime.parse("2015-08-18T00:00+01:00")

This throws a parse exception:

java.time.ZonedDateTime.parse("2015-08-18T00:00+01")

From the iso8601 wikipedia page:

The offset from UTC is appended to the time in the same way that 'Z' was above, in the form ±[hh]:[mm], ±[hh][mm], or ±[hh]. So if the time being described is one hour ahead of UTC (such as the time in Berlin during the winter), the zone designator would be "+01:00", "+0100", or simply "+01".

EDIT: This looks like an actual legitimate bug in the JDK.

https://bugs.openjdk.java.net/browse/JDK-8032051

Wow, after testing that new date time stuff for years, I thought they would have caught something so obvious. I also thought the JDK author types were rigorous enough to use a better automated test suite.

UPDATE: This is completely fixed in the current jdk-9 build. I just confirmed. The exact same parse command showed above fails in the current jdk-8 build and works perfectly in jdk-9.

ADDENDUM: FWIW, RFC 3339 based on ISO-8601, does not allow for this short hand. You must specify minutes in the time zone offsets.

Answer 1

The code which is used is added by DateTimeFormatterBuilder.appendZoneId() which allows the formats for time zone as

For example, the following will parse:

"Europe/London"           -- ZoneId.of("Europe/London")
"Z"                       -- ZoneOffset.UTC
"UT"                      -- ZoneId.of("UT")
"UTC"                     -- ZoneId.of("UTC")
"GMT"                     -- ZoneId.of("GMT")
"+01:30"                  -- ZoneOffset.of("+01:30")
"UT+01:30"                -- ZoneOffset.of("+01:30")
"UTC+01:30"               -- ZoneOffset.of("+01:30")
"GMT+01:30"               -- ZoneOffset.of("+01:30")

You can define your own date time format to allow hour offsets, but many places in the world have fractions of an hour such as Nepal which is +05:45 and North Korea which recently changed to +08:30