PQ83417: CLASSCASTEXCEPTION CAN OCCUR WHEN CONNECTING TO MULTIPLE BACK-END DATABASES, FROM THE SAME WEBSPHERE SERVER.

APAR status
Closed as documentation error.

Error description
When the customer attempts to perform a lookup of a datasource,
and cast to 'javax.sql.DataSource', the application may
experience a ClassCastException.

This occurs when there are multiple back-end databases
being used from the same WebSphere Application Server.
Sample Stack Trace:
.
Trace: 2004/01/12 21:42:49.771 01 t=9D7A60 c=4.1 key=P8
(13007002).
 FunctionName: com.ibm.servlet.engine.srt.WebGroup.
 SourceId: com.ibm.servlet.engine.srt.WebGroup.
Category: ERROR.
ExtendedMessage: Servlet Error: "":
java.lang.ClassCastException.
.at oracle.OracleDBPoolAccess.obtainConnection
(OracleDBPoolAccess.java:43)
.at oracle.OracleConPooling.doPost(OracleConPooling.java:48).
.at oracle.OracleConPooling.doGet(OracleConPooling.java:32)
.at javax.servlet.http.HttpServlet.service(HttpServlet.java:740)
javax.servlet.http.HttpServlet.service(HttpServlet.java:853).
Local fix Problem summary
****************************************************************
* USERS AFFECTED: All users of WebSphere Application Server    *
*                 version 4.0.1 for z/OS and OS/390            *
****************************************************************
* PROBLEM DESCRIPTION: An application may experience a         *
*                      ClassCastException when a customer      *
*                      attempts to perform a lookup of a       *
*                      datasource, and cast to                 *
*                      'javax.sql.DataSource'.                 *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
When the customer attempts to perform a lookup of a datasource,
and cast to 'javax.sql.DataSource', the application may
experience a ClassCastException. This occurs when there are
multiple back-end databases being used from the same
WebSphere Application Server.
Problem conclusion
In a WebSphere for z/OS V4.0.1 environment, Users of certain
Type 4 JDBC Connector Drivers may encounter a ClassCastException
after looking up a DataSource and casting to the
(javax.sql.DataSource) interface. Adding the Type 4 JDBC
Connector Drivers' JAR file(s) to the CLASSPATH environment
variable for the appropriate J2EE application server and
removing the directory containing these JAR  files from the
values specified on the WS_EXT_DIRS environment variable might
prevent  this problem from occurring.

The following information will be added to "WebSphere
Application Server V4.0.1 for z/OS: Assembling J2EE
Applications," SA22-7836-06. To access the latest
online documentation, go to the product library page at:

www.ibm.com/software/webservers/appserv/zos_os390/library/

In Chapter 16, the following note will be added to the eighth
step in the section "Steps for creating a Resource Factory
for the Type 4 JDBC Connector:"

Note: Users of certain Type 4 JDBC Connector Drivers might
encounter a ClassCastException after looking up a DataSource
and casting to the (javax.sql.DataSource) interface.  Adding
the Type 4 JDBC Connector Drivers' JAR file(s) to the
CLASSPATH environment variable for the appropriate J2EE
application server and removing the directory containing
these JAR  files from the values specified on the WS_EXT_DIRS
environment variable might prevent  this problem from
occurring.

This same note will also be added to the fourth step in the
Chapter 16 section "Steps for developing and deploying
applications."
Temporary fix Comments
APAR information
APAR number PQ83417
Reported component name WASKBASE
Reported component ID 5655A9801
Reported release 401
Status CLOSED DOC
PE NoPE
HIPER NoHIPER
Submitted date 2004-01-19
Closed date 2004-04-21
Last modified date 2004-04-21

APAR is sysrouted FROM one or more of the following:

APAR is sysrouted TO one or more of the following:

Modules/Macros

Fix information

Applicable component levels


Document Information


Product categories: Software > Application Servers > Distributed Application & Web Servers > WebSphere Application Server for z/OS
Operating system(s):
Software version: 401
Software edition:
Reference #: PQ83417
IBM Group: Software Group
Modified date: Apr 21, 2004