Re: [castor-dev] java.util.ConcurrentModificationException when change tomcat3.2 to tomcat4.0

[Brad Clow]

we have had the same problem with a combination of castor and poolman (we don't use tomcat, but i can c that u r using poolman from the stack trace).   i am not sure if it is a poolman or a castor problem yet, haven't had time to investigate it thoroughly.  to get around it, u can comment out lines 127-132 in com.codestudio.sql.PoolManConnection.java & rebuild poolman.  this section of code is simply cleaning up un-closed statements on the connection being closed.  this may result in a memory leak, but it will let u continue development until the problem is solved properly.   brad  -----Original Message----- From: cwd [mailto:[EMAIL PROTECTED]] Sent: Friday, 4 January 2002 4:50 PM To: [EMAIL PROTECTED] Subject: [castor-dev] java.util.ConcurrentModificationException when change tomcat3.2 to tomcat4.0 Hi all, I meet a very strange problem when change tomcat3.2 to tomcat4.0 my program is:        db.begin();     oql = db.getOQLQuery( "select u from ua.module.uaserver.User u WHERE login=$1 and type=$2" );    oql.bind( "llll" );    oql.bind( "4");    System.out.println("Readonly .. ");    results = oql.execute( Database.ReadOnly );    if ( results.hasMoreElements() ) {     theUser = (User)results.nextElement();    }              results2 = null;        Merchant m = null;    oql2 = db.getOQLQuery( "select u from ua.module.uaserver.Merchant u " );    file://oql.bind( "000002" );    results2 = oql2.execute( Database.ReadOnly );    System.out.println("Readonly .. ");    if ( results2 .hasMoreElements() ) {          m = (Merchant) results2.nextElement();     System.out.println(m);    }    if (m == null){     System.out.println("no such merchant");     return "failure";    }     db.commit();   when excute this servlet,I saw these exceptions:             at java.util.HashMap$HashIterator.next(HashMap.java:736)         at java.util.WeakHashMap$1.hasNext(WeakHashMap.java:369)         at java.util.AbstractMap$2.hasNext(AbstractMap.java:364)         at com.codestudio.sql.PoolManConnection.clean(Unknown Source)         at com.codestudio.util.JDBCPool.returnConnection(Unknown Source)         at com.codestudio.util.JDBCPool.connectionClosed(Unknown Source)         at com.codestudio.sql.PoolManConnection.sendCloseEvent(Unknown Source)         at com.codestudio.sql.PoolManConnectionHandle.close(Unknown Source)         at org.exolab.castor.jdo.engine.TransactionContextImpl.commitConnections (TransactionContextImpl.java:133)         at org.exolab.castor.persist.TransactionContext.commit(TransactionContex t.java:1532)         at org.exolab.castor.jdo.engine.DatabaseImpl.commit(DatabaseImpl.java:50 0)         at ua.module.web.BaseAction.perform(BaseAction.java:118)         at org.apache.struts.action.ActionServlet.processActionPerform(ActionSer vlet.java:1621)         at org.apache.struts.action.ActionServlet.process(ActionServlet.java:143 1)         at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:463)         at javax.servlet.http.HttpServlet.service(HttpServlet.java:740)         at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)         at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Appl icationFilterChain.java:247)         at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationF ilterChain.java:193)         at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperV alve.java:243)         at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline .java:566)         at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.jav a:472)         at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)           at org.apache.catalina.core.StandardContextValve.invoke(StandardContextV alve.java:201)         at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline .java:566)         at org.apache.catalina.valves.CertificatesValve.invoke(CertificatesValve .java:246)         at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline .java:564)         at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.jav a:472)         at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)           at org.apache.catalina.core.StandardContext.invoke(StandardContext.java: 2344)         at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.j ava:164)         at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline .java:566)         at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatche rValve.java:170)         at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline .java:564)         at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.j ava:170)         at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline .java:564)         at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java: 462)         at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline .java:564)         at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.jav a:472)         at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)           at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineVal ve.java:163)         at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline .java:566)         at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.jav a:472)         at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)           at org.apache.catalina.connector.http.HttpProcessor.process(HttpProcesso r.java:1011)         at org.apache.catalina.connector.http.HttpProcessor.run(HttpProcessor.ja va:1106)         at java.lang.Thread.run(Thread.java:484)