Artur Kronenberg created DROOLS-1030:
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Summary: Nullpointer in JpaTimerJobInstance.call on startup
Key: DROOLS-1030
URL:
https://issues.jboss.org/browse/DROOLS-1030
Project: Drools
Issue Type: Feature Request
Components: core engine
Environment: Mac OS 10.10.5, Eclipse Mars Release, Java 1.8, Drools 6.3.0.Final
Reporter: Artur Kronenberg
Assignee: Mario Fusco
Hi,
I have noticed Nullpointer exceptions when I try and reload a persisted session on
startup. It is a bit hard to recreate (I am actually not managing it now since I deleted
all old sessions to attempt recreation) but I figured maybe someone has an idea.
Essentially I am getting this NPE twice:
java.lang.NullPointerException: null
at
org.drools.persistence.jpa.JpaTimerJobInstance.call(JpaTimerJobInstance.java:50)
[drools-persistence-jpa-6.3.0.Final.jar:6.3.0.Final]
at
org.drools.persistence.jpa.JpaTimerJobInstance.call(JpaTimerJobInstance.java:30)
[drools-persistence-jpa-6.3.0.Final.jar:6.3.0.Final]
at java.util.concurrent.FutureTask.run(FutureTask.java:266) [na:1.8.0_51]
at
java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180)
[na:1.8.0_51]
at
java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)
[na:1.8.0_51]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
[na:1.8.0_51]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
[na:1.8.0_51]
at java.lang.Thread.run(Thread.java:745) [na:1.8.0_51]
When debugging I noticed the following behaviour which points to a race condition:
If I start my server and try to recreate the session, those NPEs happen 2x.
If I start my server and put a breakpoint BEFORE creating the CommandService for
execution, I can wait for a few seconds and the service can be found.
It appears that the scheduler's timerJobFactoryManager is not fully there at the time
the sessions is being loaded? Or something else is racing with the service creation.
Is there a way for me to make sure everything is fully instantiated before I use drools?
Does a workaround exist? Is this even a bug?
Thanks and let me know your thoughts. If I run into this again I will attempt to try and
reproduce it. Let me know if more info is needed!
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