DataSource[Connection Pool] -- suddenly lost

[lzj0428]

Hi, I am using JBoss 3.2.6 and JDK 1.4.2_06,
config a datasource with mysql-ds.xml,
but sometimes, JBoss console shows these 3 lines:

DEBUG [org.jboss.util.NestedThrowable] org.jboss.util.NestedThrowable.parentTraceEnabled=true
DEBUG [org.jboss.util.NestedThrowable] org.jboss.util.NestedThrowable.nestedTraceEnabled=false
DEBUG [org.jboss.util.NestedThrowable] org.jboss.util.NestedThrowable.detectDuplicateNesting=true

And then, every Connection getting from DataSource
return null object, throws NullPointerException.

Is there any way to solve the problem?
Ivan Liu
mysql-ds.xml :
<?xml version="1.0" encoding="UTF-8"?>
<!-- $Id: mysql-ds.xml,v 1.1.2.1 2003/12/12 19:19:56 starksm Exp $ -->
<!-- Datasource config for MySQL using 3.0.9 available from:
http://www.mysql.com/downloads/api-jdbc-stable.html
-->

<local-tx-datasource>
<jndi-name>DefaultDS</jndi-name>
<connection-url>jdbc:mysql://host:3306/abcdb</connection-url>
<driver-class>com.mysql.jdbc.Driver</driver-class>
<user-name>user</user-name>
pwd

<type-mapping>MySQL</type-mapping>

<min-pool-size>2</min-pool-size>
<max-pool-size>20</max-pool-size>
<idle-timeout-minutes>1</idle-timeout-minutes>
<check-valid-connection-sql>SELECT COUNT(*) FROM K_USER</check-valid-connection-sql>
<blocking-timeout-millis>10000</blocking-timeout-millis>
</local-tx-datasource>

[lzj0428]

We found there is one JSP page
which get Conncetion from that DataSource,
but forgot to return Connection or close it.

After a period of time, that kind of connection
will be left beyond control,
until it reached max pool size,
new connection fail to get from Connection Pool.
Cause the server crash and must be restart....

Now system works fine. Hope this is the answer.