I get the exception that is listed below and i really cant find out why. The exception dont always come, but when its thrown is there nothing i can do except restarting the Tomcat Service, when i have done that it can run for
Im using v2.0 of Hibernate and MySql v4 on a Tomcat 5.5


Here is the full stracktrace:


2005-08-31 02:39:34 StandardWrapperValve[saleDetails.jsp]: Servlet.service() for servlet saleDetails.jsp threw exception
java.lang.NullPointerException
at org.apache.jsp.ShowGallery.saleDetails_jsp._jspService(saleDetails_jsp.java:63)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:324)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:237)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:214)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:152)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:118)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:799)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:705)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:577)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
at java.lang.Thread.run(Thread.java:534)

2005-08-31 08:13:26 StandardWrapperValve[jsp]: Servlet.service() for servlet jsp threw exception
java.lang.RuntimeException: net.sf.hibernate.exception.GenericJDBCException: Could not execute query
at hibernate.xml.dm.Forsale.getForsaleDataList(Forsale.java:137)
at sale.bl.gallery.GetForsaleData.getRecordsForGallery(GetForsaleData.java:30)
at org.apache.jsp.ShowGallery.gallery_jsp._jspService(gallery_jsp.java:139)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:324)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:237)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:214)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:152)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:118)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:799)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:705)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:577)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
at java.lang.Thread.run(Thread.java:534)
Caused by: net.sf.hibernate.exception.GenericJDBCException: Could not execute query
at net.sf.hibernate.exception.ErrorCodeConverter.handledNonSpecificException(ErrorCodeConverter.java:90)
at net.sf.hibernate.exception.ErrorCodeConverter.convert(ErrorCodeConverter.java:79)
at net.sf.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:30)
at net.sf.hibernate.impl.SessionImpl.convert(SessionImpl.java:4110)
at net.sf.hibernate.impl.SessionImpl.find(SessionImpl.java:1556)
at net.sf.hibernate.impl.QueryImpl.list(QueryImpl.java:39)
at hibernate.xml.dm.Forsale.getForsaleDataList(Forsale.java:133)
... 32 more
Caused by: java.sql.SQLException: Lost connection to server during query
at org.gjt.mm.mysql.Connection.execSQL(Unknown Source)
at org.gjt.mm.mysql.PreparedStatement.executeQuery(Unknown Source)
at net.sf.hibernate.impl.BatcherImpl.getResultSet(BatcherImpl.java:88)
at net.sf.hibernate.loader.Loader.getResultSet(Loader.java:875)
at net.sf.hibernate.loader.Loader.doQuery(Loader.java:269)
at net.sf.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:133)
at net.sf.hibernate.loader.Loader.doList(Loader.java:1033)
at net.sf.hibernate.loader.Loader.list(Loader.java:1024)
at net.sf.hibernate.hql.QueryTranslator.list(QueryTranslator.java:854)
at net.sf.hibernate.impl.SessionImpl.find(SessionImpl.java:1553)
... 34 more

Which connection pool are you using?

Please post your config files.

Here is my config file:

<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 2.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-2.0.dtd">

<!-- DO NOT EDIT: This is a generated file that is synchronized -->
<!-- by MyEclipse Hibernate tool integration. -->
<hibernate-configuration>

<session-factory>
<!-- properties -->
<property name="connection.username">root</property>
<property name="connection.url">jdbc:mysql://localhost:3306/sale</property>
<property name="dialect">net.sf.hibernate.dialect.MySQLDialect</property>
<property name="connection.password"></property>
<property name="connection.driver_class">org.gjt.mm.mysql.Driver</property>
<property name="show_sql">true</property>

<!-- mapping files -->
<mapping resource="hibernate/xml/dm/Forsale.hbm.xml"/>
<mapping resource="hibernate/xml/dm/Tmpimage.hbm.xml"/>
<mapping resource="hibernate/xml/dm/Images.hbm.xml"/>
<mapping resource="hibernate/xml/dm/Vote.hbm.xml"/>
<mapping resource="hibernate/xml/dm/Buy.hbm.xml"/>

</session-factory>

</hibernate-configuration>

Do these errors occur after the application has been running for a while?

There is a known issue with the built in connection pool for hibernate, mainly that it's awful and clearly marked as awful.

Either use C3P0 connection pooling or a JNDI datasource.



This is a sample C3P0 connection pool. Try it and see if it works.

Yes, it come after some time!
I did not know that there were some issues with Hibernate's connection pool!

Ill look into another solution tomorrow for connection. Perhaps you can suggest at very good open source ??

Thx for the reply :-)

Use C3P0 then. Problem solved.

Ok, ill use that for connection.
Just wondering why they not have solved it if there is a problem ?

Thank you for the help

I don't think they plan to solve it, because they say the Hibernate connection pool it's not for production use. Development only.

Okay - sounds interesting. I used the Hibernate that there is build in MyEclipseIde and they use Hibernate's own connection-pool, so i assumed that it were working allright. Wonder if i should let MyEclipseIde take a look at this threat then.

I'd imagine most people are quite aware of this and the prominent warning is quite a giveaway. The hibernate pool is used by default as most people will usually pick the most suitable connection pool for the purpose, but it is necessary to provide some form of connection pool to get people started.