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MySql, JBoss error: NPE @ org.jboss.mx.loading.loadmgr3 .beginloadtask

Andrew Lohans
Greenhorn

Joined: May 16, 2005
Posts: 4
Hey gang,

Here's my error - I'm running MySQL ver 4.0, with struts 1.2.4, hibernate 2 & jboss version 4.0.1. I use Windows XP, and the MySQL server was started with the net start MySQL command. Sadly, I don't have internet access at home (just moved in) so I'm going to be a bit loose with the details - I'll put in the full error message tomorrow if need be.

Essentially, when I do a search on the database from the webapp that I've deployed, I get a:
java.lang.nullpointerException
at org.jboss.mx.loading.loadmgr3.beginloadtask(loadmgr3.java: 153)
... (some more errors here)
at java.util.timerThread.mainloop (timer.java 432)
at java.util.timerThread.run (timer.java 382)
... (and some more here too)

This error, as far as I can tell, is related to MySQL - but seeing as it's a jboss error spat out, I've snuck it in here. The reason I suspect MySQL is that if I run a net stop MySQL command on the cmd prompt, then net start MySQL again, I can pull from the database.

I threw in c3p0 into the mix, and foud that after about 2 hours c3p0 lost connection with MySQL - effectively throwing the above error with [INFO] statements.

I'm not too familiar with MySQL here - I thought it disconnected after 8hrs generally - could this be the case? If so, isn't the datapool meant to handle this? I'd appreciate any help in the matter!

Cheers,
Andrew
Daniel Webster
Greenhorn

Joined: Dec 04, 2003
Posts: 1
I get the exact same exception and same line number problem when redeploying Cryptix PGP in jboss:

This only happens when I reload my web app from hot-deploy. That is,
  • I can deploy the web application before I start the server, start the server, and it starts fine.
  • I can start the server without the webapp, then deploy the webapp, and the program starts fine
  • If I have the webapp running, then deploy the new webapp over it, it bombs.

  • This is the exact line of code that gives the error. I have a minimal test case that loads this line in a server upon startup:

    I am running jboss 4.0.1 with cryptix (recent version, cannot find version number). I was wondering if this points to some more general problem in the jboss classloader instead of a cryptix or MySql problem?
    [ May 23, 2005: Message edited by: Daniel Webster ]
    Rick Merc
    Greenhorn

    Joined: Jun 10, 2005
    Posts: 1
    I am getting exact same error:

    2005-06-10 22:32:15,848 ERROR [org.jboss.web.localhost.Engine] ApplicationDispatcher[/hrub] Servlet.service() for servlet jsp threw exception
    java.lang.NullPointerException
    at org.jboss.mx.loading.LoadMgr3.beginLoadTask(LoadMgr3.java:153)
    at org.jboss.mx.loading.RepositoryClassLoader.loadClassImpl(RepositoryClassLoader.java:464)
    at org.jboss.mx.loading.RepositoryClassLoader.loadClass(RepositoryClassLoader.java:374)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:235)
    at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:302)
    at java.lang.Class.forName0(Native Method)
    etc...

    Again this happens during hot redeployment only. I am using jboss 4.0.1.sp1 with mysql. I tried net stop mysql but to no avail.
    micke berg
    Greenhorn

    Joined: Jun 15, 2005
    Posts: 1
    I have also have the same problem. No errormessages at deploy/startup of the server.
    Using jboss-4.0.1RC2, j2sdk1.4.2_06, mysql-4.1.12-win32 running it all in winXP. Building an application with Hibernate2 and springframework.

    java.lang.NullPointerException
    org.jboss.mx.loading.LoadMgr3.beginLoadTask(LoadMgr3.java:153)
    org.jboss.mx.loading.RepositoryClassLoader.loadClassImpl(RepositoryClassLoader.java:464)
    org.jboss.mx.loading.RepositoryClassLoader.loadClass(RepositoryClassLoader.java:374)
    java.lang.ClassLoader.loadClass(ClassLoader.java:235)
    java.lang.ClassLoader.loadClassInternal(ClassLoader.java:302)
    net.sf.ehcache.Cache.put(Cache.java:317)
    net.sf.hibernate.cache.EhCache.put(EhCache.java:148)
    net.sf.hibernate.cache.ReadOnlyCache.put(ReadOnlyCache.java:45)
    net.sf.hibernate.impl.SessionImpl.initializeEntity(SessionImpl.java:2214)
    net.sf.hibernate.loader.Loader.initializeEntitiesAndCollections(Loader.java:315)
    net.sf.hibernate.loader.Loader.doQuery(Loader.java:305)
    net.sf.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:133)
    net.sf.hibernate.loader.Loader.doList(Loader.java:1033)
    net.sf.hibernate.loader.Loader.list(Loader.java:1024)
    net.sf.hibernate.loader.CriteriaLoader.list(CriteriaLoader.java:118)
    net.sf.hibernate.impl.SessionImpl.find(SessionImpl.java:3613)
    net.sf.hibernate.impl.CriteriaImpl.list(CriteriaImpl.java:238)
    org.springframework.orm.hibernate.HibernateTemplate$5.doInHibernate(HibernateTemplate.java:415)
    org.springframework.orm.hibernate.HibernateTemplate.execute(HibernateTemplate.java:312)
    org.springframework.orm.hibernate.HibernateTemplate.loadAll(HibernateTemplate.java:411)
    Oystein Pettersen
    Greenhorn

    Joined: Jun 15, 2005
    Posts: 2
    Yup get the same error. Using jboss 4.0.1, mysql, hibernate and spring.

    This is also only when I hot deploy over a current running version of my app.

    I also think that this is a jboss classloading thing. My theory is that if I move my dep jars from my "war lib" location to jboss/server/default/lib then the classloader will not get so confused.

    The reason why I have not tested this before is that I want my app to be self contained. This means that everything that the app needs should be in the war.

    I'll try this now and repost.

    Cheers
    [ June 15, 2005: Message edited by: Oystein Pettersen ]
    Oystein Pettersen
    Greenhorn

    Joined: Jun 15, 2005
    Posts: 2
    This page shows that this is a problem in the JBossMX. The issue is still open.

    http://jira.jboss.com/jira/browse/JBAS-1712

    I got rid of the NPE by adding the mysql-connector.jar to the jboss/server/default/lib directory.

    I do not like this bug workaround but I helps me avoiding to stop and start the jboss all the time.

    Cheers
    [ June 15, 2005: Message edited by: Oystein Pettersen ]
     
    It is sorta covered in the JavaRanch Style Guide.
     
    subject: MySql, JBoss error: NPE @ org.jboss.mx.loading.loadmgr3 .beginloadtask
     
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