StaxEventItemWriter throws NullPointerException

[eknathtieto]

Hi,
i am using StaxEventItemWriter in my code to transfer the data from the database to physical files.

The beans confiuration as below
!-- Archiving the Data from the PWHH database to physical files and then deleting the Files -->
<batch:job id="archiveToDiskJob" restartable="true">
<batch:step id="archivingStep" >
<batch:tasklet transaction-manager="histTransactionManager">
<batch:chunk
commit-interval="${archivingStep.commitInterval}"
retry-limit="1"
reader="archivingItemReader"
writer="archivingItemWriter"
throttle-limit="1"
task-executor="jobLauncherTaskExecutor"
skip-limit="1">
<batch:retryable-exception-classes>
org.springframework.dao.DeadlockLoserDataAccessExc eption
</batch:retryable-exception-classes>
<batch:skippable-exception-classes>
org.springframework.batch.core.step.item.FaultTole rantChunkProvider
</batch:skippable-exception-classes>
<batch:streams>
<batch:stream ref="archivingStaxEventItemWriter"/>
</batch:streams>
</batch:chunk>
<batch:listeners>
<batch:listener ref="genericItemFailureListener" />
</batch:listeners>
</batch:tasklet>
</batch:step>
</batch:job>

<!--Reading the PWHH database to Archive -->
<bean id="archivingItemReader" class="com.te.pwh.services.history.jobs.Historical izationItemReader" scope="step">
<property name="jdbcTemplate">
<bean class="org.springframework.jdbc.core.JdbcTemplate" >
<property name="dataSource" ref="pwhHistoryDatasource" />
</bean>
</property>
<property name="paymentFileDao" ref="historicPaymentFileDao" />
<property name="numFileRows" value="${historicalizationStep.fileFetchRowSize}" />
</bean>

<!--Translating data from PWHH database to physical File -->
<bean name="archivingItemWriter" class="org.springframework.batch.item.support.Comp ositeItemWriter" scope="step">
<property name="delegates">
<list>
<ref bean="archivingStaxEventItemWriter" />
<bean class="com.te.pwh.services.history.jobs.DeletePaym entFileItemWriter">
<property name="historicalizationPaymentFileDao" ref="historyHistoricalizationPaymentFileDao" />
</bean>
</list>
</property>
</bean>

<!--Writing data into physical file -->
<bean id="archivingStaxEventItemWriter" class="org.springframework.batch.item.xml.StaxEven tItemWriter" scope="step">
<property name="resource" ref="archiveFile" />
<property name="rootTagName" value="Root" />
<property name="overwriteOutput" value="false" />
<property name="marshaller" ref="archivingFilesMarshaller" />
</bean>

<bean id="archiveFile" class="org.springframework.core.io.FileSystemResou rce" scope="step">
<constructor-arg type="java.io.File" value="${archiveFile.filePattern}#{stepExecutionCo ntext['archvingFile']}" />
</bean>

<bean id="archivingFilesMarshaller" class="org.springframework.oxm.xstream.XStreamMars haller">
<property name="aliases">
<util:map id="aliases" map-class="java.util.HashMap">
<entry key="Tpwpayfi" value="com.te.pwh.hibernate.Tpwpayfi" />
</util:map>
</property>
</bean>

But after some time i am getting the NullPointerException. Stack strace is below

Help is appreciated .

/10/2010 20:44:53,484 [WorkManager.PwhWorkManager : 0] ERROR org.springframework.batch.core.step.AbstractStep - Encountered an error executing the step
java.lang.NullPointerException at org.springframework.batch.repeat.support.RepeatTem plate.canContinue(RepeatTemplate.java:391)

at org.springframework.batch.repeat.support.TaskExecu torRepeatTemplate.waitForResults(TaskExecutorRepea tTemplate.java:188)
at org.springframework.batch.repeat.support.RepeatTem plate.executeInternal(RepeatTemplate.java:231)
at org.springframework.batch.repeat.support.RepeatTem plate.iterate(RepeatTemplate.java:143)
at org.springframework.batch.core.step.tasklet.Taskle tStep.doExecute(TaskletStep.java:242)
at org.springframework.batch.core.step.AbstractStep.e xecute(AbstractStep.java:198)
at org.springframework.batch.core.job.AbstractJob.han dleStep(AbstractJob.java:348)
at org.springframework.batch.core.job.flow.FlowJob.ac cess$100(FlowJob.java:43)
at org.springframework.batch.core.job.flow.FlowJob$Jo bFlowExecutor.executeStep(FlowJob.java:135)
at org.springframework.batch.core.job.flow.support.st ate.StepState.handle(StepState.java:60)
at org.springframework.batch.core.job.flow.support.Si mpleFlow.resume(SimpleFlow.java:144)
at org.springframework.batch.core.job.flow.support.Si mpleFlow.start(SimpleFlow.java:124)
at org.springframework.batch.core.job.flow.FlowJob.do Execute(FlowJob.java:103)
at org.springframework.batch.core.job.AbstractJob.exe cute(AbstractJob.java:250)
at org.springframework.batch.core.launch.support.Simp leJobLauncher$1.run(SimpleJobLauncher.java:110)
at org.springframework.core.task.SyncTaskExecutor.exe cute(SyncTaskExecutor.java:49)
at org.springframework.batch.core.launch.support.Simp leJobLauncher.run(SimpleJobLauncher.java:105)
at com.te.pwh.services.history.jobs.QuartzBatchLaunch erJob.executeJob(QuartzBatchLauncherJob.java:221)
at com.te.pwh.services.history.jobs.QuartzBatchLaunch erJob.executeInternal(QuartzBatchLauncherJob.java: 79)
at org.springframework.scheduling.quartz.QuartzJobBea n.execute(QuartzJobBean.java:86)
at org.quartz.core.JobRunShell.run(JobRunShell.java:2 02)
at org.springframework.scheduling.commonj.DelegatingW ork.run(DelegatingWork.java:61)
at com.ibm.ws.asynchbeans.J2EEContext.run(J2EEContext .java:1112)
at com.ibm.ws.asynchbeans.WorkWithExecutionContextImp l.go(WorkWithExecutionContextImpl.java:195)
at com.ibm.ws.asynchbeans.CJWorkItemImpl.run(CJWorkIt emImpl.java:187)
at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.j ava:1498)

[Dave Syer]

The NPE is nothing to do with the ItemWriter is it? What version of Spring Batch are you using?

Using a task executor in your step with throttle-limit=1 is pointless. And the StaxEventItemWriter is not thread safe (the Javadocs say it is not), so using a task executor at all is probably a mistake. If you remove those settings does it work?

There's another potential error in your configuration: I doubt if it is ever correct to use a different transaction manager for your step than the job.

(Please use [code][/code] tags to post code and stack traces.)

P.S. posting duplicates won't help get you an answer - it might just irritate people.

[eknathtieto]

Thanks a quick reply.

Yes, i agree with you NPE is noothing to do with ItemWriter.


I am using the spring batch version 2.0.4.RELEASE.

I have removed the task executor from the step, i have also removed the transaction manager from the step.

I have tested with above setting and got the Out of Memory error

Plasese help for this .

<code> <batch:job id="archiveToDiskJob" restartable="true">
<batch:step id="archivingStep">
<batch:tasklet>
<batch:chunk
commit-interval="${archivingStep.commitInterval}"
retry-limit="1"
reader="archivingItemReader"
writer="archivingItemWriter"
throttle-limit="1"
skip-limit="1">
<batch:retryable-exception-classes>
org.springframework.dao.DeadlockLoserDataAccessExc eption
</batch:retryable-exception-classes>
<batch:skippable-exception-classes>
org.springframework.batch.core.step.item.FaultTole rantChunkProvider
</batch:skippable-exception-classes>
<batch:streams>
<batch:stream ref="archivingStaxEventItemWriter"/>
</batch:streams>
</batch:chunk>
<batch:listeners>
<batch:listener ref="genericItemFailureListener" />
</batch:listeners>
</batch:tasklet>
</batch:step>

</batch:job>

<!--Reading the PWHH database to Archive -->
<bean id="archivingItemReader" class="com.te.pwh.services.history.jobs.Historical izationItemReader" scope="step">
<property name="jdbcTemplate">
<bean class="org.springframework.jdbc.core.JdbcTemplate" >
<property name="dataSource" ref="pwhHistoryDatasource" />
</bean>
</property>
<property name="paymentFileDao" ref="historicPaymentFileDao" />
<property name="numFileRows" value="${historicalizationStep.fileFetchRowSize}" />
</bean>

<!--Translating data from PWHH database to physical File -->
<bean name="archivingItemWriter" class="org.springframework.batch.item.support.Comp ositeItemWriter">
<property name="delegates">
<list>
<ref bean="archivingStaxEventItemWriter" />
<bean class="com.te.pwh.services.history.jobs.DeletePaym entFileItemWriter">
<property name="historicalizationPaymentFileDao" ref="historyHistoricalizationPaymentFileDao" />
</bean>
</list>
</property>
</bean>

<!--Writing data into physical file -->
<bean id="archivingStaxEventItemWriter" class="org.springframework.batch.item.xml.StaxEven tItemWriter">
<property name="resource" ref="archiveFile" />
<property name="rootTagName" value="Root" />
<property name="overwriteOutput" value="false" />
<property name="marshaller" ref="archivingFilesMarshaller" />
</bean>

<bean id="archiveFile" class="org.springframework.core.io.FileSystemResou rce" scope="step">
<constructor-arg type="java.io.File" value="${archiveFile.filePattern}#{jobParameters['archvingFile']}" />
</bean>

<bean id="archivingFilesMarshaller" class="org.springframework.oxm.xstream.XStreamMars haller">
<property name="aliases">
<util:map id="aliases" map-class="java.util.HashMap">
<entry key="Tpwpayfi" value="com.te.pwh.hibernate.Tpwpayfi" />
<entry key="Tpwpaygr" value="com.te.pwh.hibernate.Tpwpaygr" />
<entry key="Tpwpayfi" value="com.te.pwh.hibernate.Tpwpamsg" />
</util:map>
</property>
<property name="mode" value="1004"/>
</bean>
</code>

[Dave Syer]

A stack trace might help. What's your commit interval?

(Please use [code][/code] tags to post code and stack traces.)