An application programmer does not use the PooledConnection interface directly; rather, it is used by a middle tier infrastructure that manages the pooling of connections.

When an application calls the method DataSource.getConnection, it gets back a Connection object. If connection pooling is being done, that Connection object is actually a handle to a PooledConnection object, which is a physical connection.

The connection pool manager, typically the application server, maintains a pool of PooledConnection objects. If there is a PooledConnection object available in the pool, the connection pool manager returns a Connection object that is a handle to that physical connection. If no PooledConnection object is available, the connection pool manager calls the ConnectionPoolDataSource method getPoolConnection to create a new physical connection. The JDBC driver implementing ConnectionPoolDataSource creates a new PooledConnection object and returns a handle to it.

When an application closes a connection, it calls the Connection method close. When connection pooling is being done, the connection pool manager is notified because it has registered itself as a ConnectionEventListener object using the ConnectionPool method addConnectionEventListener. The connection pool manager deactivates the handle to the PooledConnection object and returns the PooledConnection object to the pool of connections so that it can be used again. Thus, when an application closes its connection, the underlying physical connection is recycled rather than being closed.

The physical connection is not closed until the connection pool manager calls the PooledConnection method close. This method is generally called to have an orderly shutdown of the server or if a fatal error has made the connection unusable.

A connection pool manager is often also a statement pool manager, maintining a pool of PreparedStatement objects. When an application closes a prepared statement, it calls the PreparedStatement method close. When Statement pooling is being done, the pool manager is notified because it has registered itself as a StatementEventListener object using the ConnectionPool method addStatementEventListener. Thus, when an application closes its PreparedStatement, the underlying prepared statement is recycled rather than being closed.