[Java] Improve the performance of JDBC adapters by using nullable information

[asfimport]

JDBC meta data has a field that indicates if a column can contain null. We can make use of this information when transforming jdbc data to arrow vectors.

In particular, if the column cannot have null, there is no need to call the JDBC API for each value to check if the last value is null.

This will improve the performance of transforming JDBC data to arrow vectors.

Reporter: Liya Fan / @liyafan82
Assignee: Liya Fan / @liyafan82

PRs and other links:

• GitHub Pull Request #5508

_{Note: This issue was originally created as ARROW-6707. Please see the migration documentation for further details.}

[asfimport]

Micah Kornfield / @emkornfield:
Issue resolved by pull request 5508
#5508