"Something unusual has occured" error using PostgreSQL 8.2 with Apache Commons DBCP 1.2.2

Hi -

I'm getting a rather disturbing exception that I really hope someone can
help me out with.

To start, I'm putting together a Java client-server app, where the
server side talks to a PostgreSQL database via an Apache Commons DBCP
link for connection pooling. Using the code I've included below, I'm
able to establish a connection, get database metadata, and execute
stored functions perfectly well PROVIDING I DON'T try to call
getConnection() again without closing the first connection beforehand.
(but it seems to me that doing that ought to work alright, because if I
call getConnection() a second time, shouldn't the DBCP code just pull a
new connection from the pool, and not, instead, throw this exception?)

To recap. This works:

Connection conn = ConnectionPool.getConnection(); // this
ConnectionPool class is one I wrote, see below for details
// do stuff with this connection
ConnectionPool.close(conn); // simply closes
the connection, catching any exceptions
conn = ConnectionPool.getConnection(); // get another
connection. this works just fine now that
// the the
connection has been
closed before this
call

But if I try this, all hell breaks loose on the second call to
getConnection():

Connection conn = ConnectionPool.getConnection();
// do stuff with this connection
Connection conn2 = ConnectionPool.getConnection(); // the exception
below would be thrown inside here

EXCEPTION:
----------
org.postgresql.util.PSQLException: Something unusual has occured to
cause the driver to fail. Please report this exception.
at org.postgresql.Driver.connect(Driver.java:276)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at
org.apache.commons.dbcp.DriverManagerConnectionFactory.createConnection(DriverManagerConnectionFactory.java:68)
at
org.apache.commons.dbcp.PoolableConnectionFactory.makeObject(PoolableConnectionFactory.java:294)
at
org.apache.commons.pool.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:840)
at
org.apache.commons.dbcp.PoolingDriver.connect(PoolingDriver.java:176)

at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at
myproject.db.ConnectionPool.getConnection(ConnectionPool.java:136)

RELATED CODE:
-------------

This is the code I use to create the connection pool and register the
driver (in my ConnectionPool constructor) - note that this works insofar
as I can connect to the database and get metadata and do queries and
stuff, so I don't think this code is screwy, but who knows?):

// some unrelated stuff up here
...
GenericObjectPool pool = new GenericObjectPool(null);
pool.setMinIdle(5);
pool.setMaxIdle(10);
pool.setMaxActive(30);
pool.setWhenExhaustedAction(GenericObjectPool.WHEN_EXHAUSTED_BLOCK);
pool.setMaxWait(1000 * 60 * 5);
pool.setSoftMinEvictableIdleTimeMillis(1000 * 60 * 30);
pool.setTimeBetweenEvictionRunsMillis(1000 * 60 * 10);

Properties props = new Properties();
props.setProperty("user", "testuser");
props.setProperty("password", "testpass");

ConnectionFactory connectionFactory = new DriverManagerConnectionFactory(
"jdbc:postgresql://localhost:5432/testdb", props);

PoolableConnectionFactory poolableConnectionFactory =
new PoolableConnectionFactory(connectionFactory,
pool, null, null, false, false);

PoolingDriver driver = new PoolingDriver();
driver.registerPool("mydb", pool);
...

------------------------------------------------------------------------

Now, when I want to retrieve a connection, I call
ConnectionPool.getConnection(), which is where the problem occurs. Note
that line 136 (from the stack trace above) is the "Connection conn =
DriverManager..." line in the code below:

public static Connection getConnection() throws SQLException {
try {
Connection conn = DriverManager.getConnection(
"jdbc:apache:commons:dbcp:mydb");
return conn;
} catch (SQLException sqle) {
System.out.println(sqle.getMessage());
sqle.printStackTrace();
throw sqle;
}
}

------------------------------------

Lastly, here are the versions of the relevant software I'm using:
- PostgreSQL 8.2.4
- PostgreSQL JDBC driver 8.2-506.jdbc4
- Java 2 SE 1.6.0_02
- Jakarta Commons Pool 1.3
- Jakarta Commons DBCP 1.2.2
- Microsoft Windows XP SP2

On a possibly related note, I read in the Apache Commons DBCP README
that says:
"This release of JDBC compiles with and supports JDK 1.3 (JDBC 2.0) and
JDK 1.4-1.5 (JDBC 3.0). JDK 1.6 (JDBC 4.0) is not supported by this
release." I'd like to try using PostgreSQL's JDBC3 drivers, but the
site says that if I'm using Java 1.6 I shouldn't use that, but should
use their JDBC4 drivers instead. Any thoughts?

Thanks a lot for any help you can provide!

Regards,

Matt Storer