Re: Should application do connection.close()?

You're good!!!

You link
http://java.sun.com/j2se/1.4.2/docs/api/javax/sql/PooledConnection.html
explain how the close method does not actually closed the connection.

Below is a clip from the link:
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.


"Joe Sam Shirah" <joe_sam@xxxxxxxxxxxxx> wrote in message
news:<mailman.11150.1237583065.26163.java400-l@xxxxxxxxxxxx>...

See "4.1.5 DataSource Implementations" at:

http://java.sun.com/javase/6/docs/technotes/guides/jdbc/getstart/datasou
rce.html#1000109

then see:

http://java.sun.com/j2se/1.4.2/docs/api/javax/sql/PooledConnection.html

If an implementation calls itself Java, then it must follow the
standards. At least it must not intentionally not follow the

standard.

That's a large part of what makes Java Java. Sort of like what is is.

To be direct to your question, which David has already answered:

Always

close at least the Connection when you're done with it. As I tried to

emphasize in my JDBC 2.0 tutorial, a defensive programmer also always

closes

the ResultSet and the Statement as soon as you're done with them.

Unless

you want performance problems and possible eventual shutdown and

database

impact. Do not depend on finalizers for anything.


Joe Sam

Joe Sam Shirah - http://www.conceptgo.com
conceptGO - Consulting/Development/Outsourcing
Java Filter Forum: http://www.ibm.com/developerworks/java/
Just the JDBC FAQs: http://www.jguru.com/faq/JDBC
Going International? http://www.jguru.com/faq/I18N
Que Java400? http://www.jguru.com/faq/Java400

----- Original Message -----
From: "Neill Harper" <neill.harper@xxxxxxxx>
To: "'Java Programming on and around the iSeries / AS400'"
<java400-l@xxxxxxxxxxxx>
Sent: Friday, March 20, 2009 4:24 PM
Subject: RE: Should application do connection.close()?

The javadoc on the ibm site says that .close() returns the

connection to

the
pool so you should deffo close it.

// Obtain an AS400JDBCConnectionPoolDataSource object from JNDI.
Context context = new InitialContext(environment);
AS400JDBCConnectionPoolDataSource datasource =

(AS400JDBCConnectionPoolDataSource)context.lookup("jdbc/myDatabase");

// Create an AS400JDBCConnectionPool object.
AS400JDBCConnectionPool pool = new

AS400JDBCConnectionPool(datasource);

// Adds 10 connections to the pool that can be used by the

application

(creates the physical database connections based on the data

source).

pool.fill(10);

// Get a handle to a database connection from the pool.
Connection connection = pool.getConnection();

... Perform miscellenous queries/updates on the database.

// Close the connection handle to return it to the pool.
connection.close();

... Application works with some more connections from the pool.

// Close the pool to release all resources.
pool.close();

-----Original Message-----
From: java400-l-bounces@xxxxxxxxxxxx
[mailto:java400-l-bounces@xxxxxxxxxxxx]
On Behalf Of David Gibbs
Sent: 20 March 2009 19:57
To: Java Programming on and around the iSeries / AS400
Subject: Re: Should application do connection.close()?

Lim Hock-Chai wrote:

When the method does AS400JDBCConnectionPool.getConnection(), it

will

return a java.sqlConnection object to the caller. I'm assuming

that the

close() method of this returned Connection object is being

overriden to

not close the connection. Instead, it put it back to the pool.

That is

just my guess. The doc does really say anyhting about this. Can

anyone

confirm?

Regardless if it returns the connection back to the pool, it's

always a

good
practice to release resources you have locked. If you don't close

the

connection, the server job will remain active waiting to service

your job.

Just like you would close a file that you explicitly opened in RPG
(assuming
it was a usropn file).

david