[Java] JDBC-to-Arrow Conversion: Unnecessary Calendar Requirement

[asfimport]

While I was going through the JDBC Adapter source code, I noticed a Calendar was required to create the Arrow Schema (for any Timestamp fields), and also needed for converting a JDBC ResultSet to an ArrowVector (for Date, Time, and Timestamp fields).

However, Arrow Timestamps do not require a time zone, and none of the JDBC getters for Date, Time, and Timestamp require a Calendar.

I am proposing a change to make the Schema creator and ResultSet converter support null Calendars. If a Calendar is available, it will be used, and if not, it will not be used.

The existing SureFire plugin configuration uses a UTC calendar for the database, which is the default Calendar in the existing code.  Likewise, no changes to the unit tests are required to provide adequate coverage for the change.

Reporter: Michael Pigott / @mikepigott
Assignee: Michael Pigott / @mikepigott

PRs and other links:

• GitHub Pull Request #3066

_{Note: This issue was originally created as ARROW-3923. Please see the migration documentation for further details.}

[asfimport]

Michael Pigott / @mikepigott:
Pull Request: #3066

[asfimport]

Uwe Korn / @xhochy:
Issue resolved by pull request 3066
#3066