Re: PSQLException: An I/O error occured while sending to the backend

If it is the firewall losing state about idle connections (and that seems a reasonably good guess), then you could try using a connection pool within the app and then configure it to test a connection before handing it back to the app. You'll need to change your architecture such that your application code calls close on a connection as soon as it is done with a transaction in order to return the connection to the pool and then retrieve a fresh connection whenever it is about to interact with the db.  For example, the commons DBCP BasicDataSource allows you to instruct it to test a connection when a connection is returned to the pool, periodically while it resides in the pool, and/or whenever a connection is retrieved from the pool.  You can specify the query that gets run to test the connection ('select 1'), etc. You can either perform idle testing frequently enough that the firewall's state table remains current, keeping the connections alive, or just allow the testOnBorrow functionality to ensure that any dead connections will be purged from the pool before they are handed to the application. If you've already got a global connection pool, then you can configure the size of the pool that is local to the application instance to be very small (or 1).