When does a Connection realise the server is down?

Question

Hi there,
I'm developing an application using (all on Win 2k Pro SP3):
- Tomcat 4.1.18
- MS SQL Server 7.1
- jTDS 0.5.1 Type 4 driver
If the application is running (i.e. within Tomcat) and the database server is stopped externally (e.g. from the Enterprise Manager) I get the following scenario:
1]
(connection == null); // still returns false
2]
(connection.isClosed()); // still returns false
3]
SQLWarning s = connection.getWarnings();
server application stops and waits at this call, a further request from the client will restart the process - i.e. the server doesn't hang.
An error isn't thrown until an attempt is made to create a ResultSet from a Statement made using this Connection (either a new or pre-exisiting Statement).
How can I check if this Connection is still usable, apart from closing and re-opening it with every call / creating a fake ResultSet for the purposes of poling the database server - which both totally defeat the purpose of having a Connection object.
Has anyone encountered this behaviour before? - perhaps it's driver specific? (jTDS 0.5.1)
Many thanks,
Fergus.

Answer 1

(connection == null); // still returns falseNot surprising since there is no situation
(unless you simply forgot to call getConnection)where
there will ever return true.Well, if you executed the line of code
connection = null;
that would return true. But in a normal
program, no.You mean if you purposely forgot to call getConnection() rather than accidently as I suggested? Yeah that would do it too. :)