java - Is there a reason for never closing a JDBC connection?

Question

I'm reading a code from the last developer that worked on the system and he never closes any connections with the database. He only closes PreparedStatement and ResultSet connections but never the Connection.

The system does not use a connection pool.

Is there any reason not to close everything (Connection, PreparedStatement and ResultSet)?

Answer 1

There is no good reason for this, it will result in a very brittle application. It's easy for a database connection to go stale if there's a network problem or if the database doesn't respond for a little while, and with the reliance on a single existing connection there's no recovering without restarting the application.

There are other bad points to this. For instance, typically connections are synchronized so if a web application with multiple concurrent users was built this way it would limit the concurrency of the application. But the inability of your application to recover from transient problems is enough to make this worth fixing.