con -- WEB400

We have running a webapp which uses 'connection-pooling' to get data from 
the iSeries.  From time to time, a selectionbox in a JSP, filled with a 
datatable is empty.  The only lead we have is an error in the std_out.log 
from WAS4.0.4

This is what we do in short:
Application loaded (basic authentication)
   JSP is loaded
   JSP initializes a databean 
   JSP executes a method from the bean
      BEAN gets a connection, using connection-pooling
      BEAN loads a table into a vector
   JSP reads vector into selection-list-box
   JSP is displayed in browser
mostly this works ok but from time to time, the selectionbox is empty...

Any suggestions???

We use WAS V4
We created the application with WSAD V4.  While testing inside WSAD we 
didn't encounter any errors.  Then I deployed the application into WAS V4 
on Win2000.  Again no errors encountered.  Finally we deployed to WAS V4 
on iSeries 270.  At first it worked but then we noticed the problem. 

This is the error displayed in log:

[16/01/03 7:54:17:516 UTC] 241eff08 StaleConnecti A CONM7007I: Mapping the 
following SQLException, with ErrorCode -99.999 and SQLState 08003, to a 
StaleConnectionException: java.sql.SQLException: The connection does not 
exist.(Connection was dropped unexpectedly.)
      java/lang/Throwable.<init>(Ljava/lang/String;)V+4 
(Throwable.java:90) 
      java/lang/Exception.<init>(Ljava/lang/String;)V+1 
(Exception.java:38) 
 java/sql/SQLException.<init>(Ljava/lang/String;Ljava/lang/String;I)V+1 
(SQLException.java:39) 
 
com/ibm/as400/access/JDError.throwSQLException(Ljava/lang/String;Ljava/lang/Exception;)V+0
 
(JDError.java:317) 
 
com/ibm/as400/access/AS400JDBCConnection.sendAndReceive(Lcom/ibm/as400/access/DBBaseRequestDS;I)Lcom/ibm/as400/access/DBReplyRequestedDS;+0
 
(AS400JDBCConnection.java:1846) 
 
com/ibm/as400/access/AS400JDBCStatement.commonExecute(Lcom/ibm/as400/access/JDSQLStatement;Lcom/ibm/as400/access/JDServerRow;)V+0
 
(AS400JDBCStatement.java:467) 
 
com/ibm/as400/access/AS400JDBCPreparedStatement.executeQuery()Ljava/sql/ResultSet;+0
 
(AS400JDBCPreparedStatement.java:827) 
 
com/ibm/ejs/cm/cache/CachedStatement.executeQuery()Ljava/sql/ResultSet;+118 
(CachedStatement.java:301) 
 
com/ibm/ejs/cm/proxy/StatementProxy.executeQueryCommon(Ljava/lang/String;Z)Ljava/sql/ResultSet;+96
 
(StatementProxy.java:274) 
 
com/ibm/ejs/cm/proxy/PreparedStatementProxy.executeQuery()Ljava/sql/ResultSet;+1
 
(PreparedStatementProxy.java:47) 
 
com/clipper/objects/Cigars.getAllCigarTypesPerClient(Ljava/sql/Connection;Ljava/lang/String;)Ljava/util/Vector;+0
 
(Cigars.java:284) 
      com/clipper/beans/CigarsBean.getCigarTypes(Ljava/lang/String;)V+0 
(CigarsBean.java:40) 
 
_CigarStock_jsp_0._jspService(Ljavax/servlet/http/HttpServletRequest;Ljavax/servlet/http/HttpServletResponse;)V+0
 
(_CigarStock_jsp_0.java:53) 
 
javax/servlet/http/HttpServlet.service(Ljavax/servlet/ServletRequest;Ljavax/servlet/ServletResponse;)V+26
 
(HttpServlet.java:853) 
 
org/apache/jasper/runtime/JspServlet$JspServletWrapper.service(Ljavax/servlet/http/HttpServletRequest;Ljavax/servlet/http/HttpServletResponse;Z)V+159
 
(JspServlet.java:312) 
 
org/apache/jasper/runtime/JspServlet.serviceJspFile(Ljavax/servlet/http/HttpServletRequest;Ljavax/servlet/http/HttpServletResponse;Ljava/lang/String;Ljava/lang/Throwable;ZLjava/lang/String;)V+92
 
(JspServlet.java:500) 
 
org/apache/jasper/runtime/JspServlet.service(Ljavax/servlet/http/HttpServletRequest;Ljavax/servlet/http/HttpServletResponse;)V+154
 
(JspServlet.java:633) 
 
javax/servlet/http/HttpServlet.service(Ljavax/servlet/ServletRequest;Ljavax/servlet/ServletResponse;)V+26
 
(HttpServlet.java:853) 
 
com/ibm/servlet/engine/webapp/StrictServletInstance.doService(Ljavax/servlet/ServletRequest;Ljavax/servlet/ServletResponse;)V+21
 
(ServletManager.java:827) 
 
com/ibm/servlet/engine/webapp/StrictLifecycleServlet._service(Ljavax/servlet/ServletRequest;Ljavax/servlet/ServletResponse;)V+69
 
(StrictLifecycleServlet.java:167) 
 
com/ibm/servlet/engine/webapp/ServletInstance.service(Ljavax/servlet/ServletRequest;Ljavax/servlet/ServletResponse;Lcom/ibm/servlet/engine/webapp/WebAppServletInvocationEvent;)V+186
 
(ServletManager.java:472) 
 
com/ibm/servlet/engine/webapp/WebAppRequestDispatcher.handleWebAppDispatch(Lcom/ibm/servlet/engine/webapp/WebAppRequest;Ljavax/servlet/http/HttpServletResponse;)V+817
 
(WebAppRequestDispatcher.java:678) 
 
com/ibm/servlet/engine/webapp/WebAppRequestDispatcher.dispatch(Ljavax/servlet/ServletRequest;Ljavax/servlet/ServletResponse;Z)V+1080
 
(WebAppRequestDispatcher.java:331) 
 
com/ibm/servlet/engine/webapp/WebAppRequestDispatcher.forward(Ljavax/servlet/ServletRequest;Ljavax/servlet/ServletResponse;)V+85
 
(WebAppRequestDispatcher.java:117) 
 
com/clipper/expedancigarstock/SLoginUser.doGet(Ljavax/servlet/http/HttpServletRequest;Ljavax/servlet/http/HttpServletResponse;)V+0
 
(SLoginUser.java:53) 
 
com/clipper/expedancigarstock/SLoginUser.doPost(Ljavax/servlet/http/HttpServletRequest;Ljavax/servlet/http/HttpServletResponse;)V+0
 
(SLoginUser.java:426) 
 
javax/servlet/http/HttpServlet.service(Ljavax/servlet/http/HttpServletRequest;Ljavax/servlet/http/HttpServletResponse;)V+136
 
(HttpServlet.java:760) 
 
javax/servlet/http/HttpServlet.service(Ljavax/servlet/ServletRequest;Ljavax/servlet/ServletResponse;)V+26
 
(HttpServlet.java:853) 
 
com/ibm/servlet/engine/webapp/StrictServletInstance.doService(Ljavax/servlet/ServletRequest;Ljavax/servlet/ServletResponse;)V+21
 
(ServletManager.java:827) 
 
com/ibm/servlet/engine/webapp/StrictLifecycleServlet._service(Ljavax/servlet/ServletRequest;Ljavax/servlet/ServletResponse;)V+69
 
(StrictLifecycleServlet.java:167) 
 
com/ibm/servlet/engine/webapp/ServletInstance.service(Ljavax/servlet/ServletRequest;Ljavax/servlet/ServletResponse;Lcom/ibm/servlet/engine/webapp/WebAppServletInvocationEvent;)V+186
 
(ServletManager.java:472) 
 
com/ibm/servlet/engine/webapp/WebAppRequestDispatcher.handleWebAppDispatch(Lcom/ibm/servlet/engine/webapp/WebAppRequest;Ljavax/servlet/http/HttpServletResponse;)V+817
 
(WebAppRequestDispatcher.java:678) 
 
com/ibm/servlet/engine/webapp/WebAppRequestDispatcher.dispatch(Ljavax/servlet/ServletRequest;Ljavax/servlet/ServletResponse;Z)V+1080
 
(WebAppRequestDispatcher.java:331) 
 
com/ibm/servlet/engine/webapp/WebAppRequestDispatcher.forward(Ljavax/servlet/ServletRequest;Ljavax/servlet/ServletResponse;)V+85
 
(WebAppRequestDispatcher.java:117) 
 
com/ibm/servlet/engine/srt/WebAppInvoker.doForward(Ljavax/servlet/http/HttpServletRequest;Ljavax/servlet/http/HttpServletResponse;)V+234
 
(WebAppInvoker.java:134) 
 
com/ibm/servlet/engine/srt/WebAppInvoker.handleInvocationHook(Ljava/lang/Object;)V+175
 
(WebAppInvoker.java:239) 
 
com/ibm/servlet/engine/invocation/CachedInvocation.handleInvocation(Ljava/lang/Object;)V+25
 
(CachedInvocation.java:67) 
 
com/ibm/servlet/engine/invocation/CacheableInvocationContext.invoke(Ljava/lang/Object;)V+87
 
(CacheableInvocationContext.java:106) 
 
com/ibm/servlet/engine/srp/ServletRequestProcessor.dispatchByURI(Ljava/lang/String;Lcom/ibm/servlet/engine/srp/ISRPConnection;)V+737
 
(ServletRequestProcessor.java:154) 
 
com/ibm/servlet/engine/oselistener/OSEListenerDispatcher.service(Lcom/ibm/servlet/engine/oselistener/api/IOSEConnection;)V+104
 
(OSEListener.java:315) 
      com/ibm/servlet/engine/http11/HttpConnection.handleRequest()V+4 
(HttpConnection.java:60) 
      com/ibm/ws/http/HttpConnection.readAndHandleRequest()V+50 
(HttpConnection.java:323) 
      com/ibm/ws/http/HttpConnection.run()V+195 (HttpConnection.java:252) 
      com/ibm/ws/util/CachedThread.run()V+18 (ThreadPool.java:137)