NPE in commons.dbcp with Hibernate, AOP and Quartz

[drvillo]

Hi all

I'm not sure this is the right place, but I don't quite know to whom this issue might belong (beside me).

I'm using quite a mix of things here: to make it simple I'm creating stateful jobs with Quartz. I'm attaching dynamic aspects to inject an Hibernate session, and to perform transaction demarcation.
Everything goes along pretty well it seems, but I don't know why after some time I begin getting the following trace.

Any comment?

java.lang.NullPointerException
	at org.apache.commons.dbcp.PoolingConnection.toString(PoolingConnection.java:248)
	at java.lang.String.valueOf(String.java:2615)
	at java.lang.StringBuffer.append(StringBuffer.java:220)
	at org.apache.commons.dbcp.DelegatingConnection.checkOpen(DelegatingConnection.java:354)
	at org.apache.commons.dbcp.DelegatingConnection.prepareStatement(DelegatingConnection.java:246)
	at org.apache.commons.dbcp.PoolingDataSource$PoolGuardConnectionWrapper.prepareStatement(PoolingDataSource.java:302)
	at org.hibernate.jdbc.AbstractBatcher.getPreparedStatement(AbstractBatcher.java:505)
	at org.hibernate.jdbc.AbstractBatcher.getPreparedStatement(AbstractBatcher.java:423)
	at org.hibernate.jdbc.AbstractBatcher.prepareQueryStatement(AbstractBatcher.java:139)
	at org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1547)
	at org.hibernate.loader.Loader.doQuery(Loader.java:673)
	at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
	at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
	at org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
	at org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
	at org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
	at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
	at org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
	at org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
	at org.hibernate.collection.PersistentSet.toArray(PersistentSet.java:171)
	at org.atalaya.isec.dashb.db.Hosts.getIp(Hosts.java:53)
	at org.atalaya.isec.appliance.nmap.NmapThread.prepare(NmapThread.java:49)
	at org.atalaya.isec.update.AScanTask.execute(AScanTask.java:62)
	at org.atalaya.isec.update.AScanTask$$FastClassByCGLIB$$f5924b97.invoke(<generated>)
	at net.sf.cglib.proxy.MethodProxy.invoke(MethodProxy.java:149)
	at org.springframework.aop.framework.Cglib2AopProxy$CglibMethodInvocation.invokeJoinpoint(Cglib2AopProxy.java:695)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:144)
	at org.springframework.aop.framework.adapter.AfterReturningAdviceInterceptor.invoke(AfterReturningAdviceInterceptor.java:50)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:166)
	at org.springframework.aop.aspectj.AspectJAfterThrowingAdvice.invoke(AspectJAfterThrowingAdvice.java:54)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:166)
	at org.springframework.aop.framework.adapter.MethodBeforeAdviceInterceptor.invoke(MethodBeforeAdviceInterceptor.java:50)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:166)
	at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:89)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:166)
	at org.springframework.aop.framework.Cglib2AopProxy$DynamicAdvisedInterceptor.intercept(Cglib2AopProxy.java:630)
	at org.atalaya.isec.appliance.nmap.NmapThread$$EnhancerByCGLIB$$4386de9a.execute(<generated>)
	at org.atalaya.isec.update.scheduling.StatefulTaskAdapter.execute(StatefulTaskAdapter.java:32)
	at org.quartz.core.JobRunShell.run(JobRunShell.java:203)

thanks everybody
Francesco

[Jörg Heinicke]

I wonder why it tries to call toString() on the connection. Are you keen enough to look into the code? Maybe it's only an error in the logging (not handling null) AFTER another exception which would be your actual error.

Joerg

[drvillo]

I've checked and the offending part is in

    protected void checkOpen() throws SQLException {
        if(_closed) {
            throw new SQLException
                ("Connection " + _conn + " is closed.");
        }
    }

so yes, it was going to throw an exception anyway.
I don't know what was messing up, I've been running the same code since this post without problem. I've a slight feeling that the combination Maven+jetty plugin+debug+all the rest might have screwed up...

Cheers
F

[Jörg Heinicke]

I have reported the issue regarding the NPE to Apache Commons DBCP Jira.

Joerg

[al0]

Anyway, it was stated many times in this forum that C3P0 produces better results then DBCP (and my own experience confirms it).

Regards,
Oleksandr

Originally Posted by drvillo

I've checked and the offending part is in

    protected void checkOpen() throws SQLException {
        if(_closed) {
            throw new SQLException
                ("Connection " + _conn + " is closed.");
        }
    }

so yes, it was going to throw an exception anyway.
I don't know what was messing up, I've been running the same code since this post without problem. I've a slight feeling that the combination Maven+jetty plugin+debug+all the rest might have screwed up...

Cheers
F

[drvillo]

Nice, thanks.
I was going to do it myself but you've been more efficient

Cheers
F

Originally Posted by Jörg Heinicke

I have reported the issue regarding the NPE to Apache Commons DBCP Jira.

Joerg

[karldmoore]

Originally Posted by al0

Anyway, it was stated many times in this forum that C3P0 produces better results then DBCP (and my own experience confirms it).

Yeah, I'd go with this one. We made the same change when we experienced problems.

[Jörg Heinicke]

Originally Posted by al0

Anyway, it was stated many times in this forum that C3P0 produces better results then DBCP

See how fast things get fixed for DBCP. Does this stand for C3P0 as well?

My vein to Apache is obvious

Joerg