This explanation goes a long way towards explaining a different issue we've had with inserting data into arrays. We use JSON for internal communications and have been seeing some weirdness with it as well. The details are different but it's another place where we're using Jackson to serialize and deserialize something. I've seen messages with both "unable to convert java.util.ArrayList to java.sql.Array" and references to PgArray.
>an not resolve type id for sun.util.calendar.ZoneInfo
This sounds like a Jackson error.
It looks like you are trying to Jackson-serialize the result of col2 column.
The column is <<time with time zone[]>>, so it is represented as PgArray object.
As Jackson serializes PgArray, it treats whatever getter it finds as a property.
It runs into PgArray#getResultSet and thinks it is a getter for resultSet property. Of course that causes it to serialize underlying statement, connection, etc.
Finally it ends up with serializing QueryExecutorImpl.timeZone field, and it fails so.
One of the recommendations might include "avoid Jackson-serializing random objects" =)
The thing is backend sends connection timezone at connection setup phase, and pgjdbc 42.2.0 ignored that. pgjdbc 42.2.1 parses timezone message in the initial parameter status messages, thus it ends up with non-null timezone, thus it fails your app.
