keeping Connection alive

Hi,

I'm using a PostgreSQL as backend for a Java application, which may idle for quite a while (i.e. hours) and now and
thenissue a query on the backend. 

The problem is the following exception I get when connection is apparently broken:

-- snip --
org.postgresql.util.PSQLException: An I/O error occured while sending to the backend.
-- snip --

What is best practice to prevent the connection from breaking, i.e. keeping the Conection alive?

I'm using an instance of PGPoolingDataSource and would expect to retrieve a _valid_ Connection when calling
DataSource.getConnection()(which I don't get). I even did call PGPoolingDataSource.setTcpKeepAlive(true) - same result. 

My first approach was to use a scheduled task and regularly check the Connection for validity ("ping") - unfortunately
Connection.isValid(inttimeout) has not been implemented yet. 

My current workaround is a scheduled task issueing a "SELECT 1" on a regularly basis. Which I feel is not the best
solution,though. 

I read of using a connection pool like dbcp, which I'd like to avoid: I don't need connection pooling at all, just need
tohave a valid Connection even after hours of no-operation (a reconnect is ok, so no performance issue here). 

So, what's the best practice using the postgresql jdbc driver?

I'm using PostgreSQL 8.3.8 and postgresql-8.4-701.jdbc4.jar for JDBC.

Thanks alot!

Best regards,
Andreas