[FlightSQLJDBC] not implemented exception when fetching TimeStamp from ResultSet

[jeremyosterhoudt]

Describe the bug, including details regarding any error messages, version, and platform.

Description

When a TimeStamp is returned in a Flight SQL JDBC ResultSet an exception is throw when accessing the value via getObject(index). It works using getObject(columnName). Below as a simple example of how the problem can be reproduced:

try (var connection = DriverManager.getConnection("jdbc:arrow-flight://localhost:5000;useEncryption=false");
 PreparedStatement createStatement = connection.prepareStatement("create table if not exists test (ts timestamp, id bigint)");
 PreparedStatement insertStatement = connection.prepareStatement("insert into test values ('1970-04-01 21:39:50', 2)");
 PreparedStatement selectStatement = connection.prepareStatement("select ts from test where id = 2")
) {

 createStatement.execute();
 insertStatement.executeUpdate();

 try (var rs = selectStatement.executeQuery()) {
 while (rs.next()) {

 // Fails with a not implemented exception
 System.out.println(rs.getObject(1)); 

 // works
 System.out.println(rs.getObject("ts")); 
 }
 }
}

Here is the stack trace for the getObject(index)

Exception in thread "main" java.lang.RuntimeException: not implemented
	at org.apache.arrow.driver.jdbc.shaded.org.apache.calcite.avatica.AvaticaSite.notImplemented(AvaticaSite.java:422)
	at org.apache.arrow.driver.jdbc.shaded.org.apache.calcite.avatica.AvaticaSite.get(AvaticaSite.java:381)
	at org.apache.arrow.driver.jdbc.shaded.org.apache.calcite.avatica.AvaticaResultSet.getObject(AvaticaResultSet.java:395)
	at JDBCParamTest.runDateTimeTimestampExample(JDBCParamTest.java:91)
	at JDBCParamTest.main(JDBCParamTest.java:14)

Version information:

item	version
Java	Zulu 21.0.8 (ARM)
Flight SQL JDBC	18.3.0
macOS	15.6 (Apple Silicon)

[lidavidm]

PRs are welcome. I'm not sure any contributor has time for the JDBC driver right now unfortunately