topic Re: org.activiti.engine.ActivitiException: couldn't instantiate class com.stud.listener.PrinterListener in Alfresco Archive

org.activiti.engine.ActivitiException: couldn't instantiate class com.stud.listener.PrinterListener

natedawg — Thu, 14 Apr 2016 13:12:19 GMT

Hi,I did try to read other similar forum posts reported on this forum but I cannot see if those are exactly the same as mine issue. So here I go. Process is attached, ending as txt as xmls are not allowed to be uploaded.The process starts with executing a service task (SequenceJob1) calling a java c

Re: org.activiti.engine.ActivitiException: couldn't instantiate class com.stud.listener.PrinterListener

natedawg — Fri, 15 Apr 2016 15:34:16 GMT

this is a big show stopper for me. I had this problem for days now.

Re: org.activiti.engine.ActivitiException: couldn't instantiate class com.stud.listener.PrinterListener

martin_grofcik — Mon, 18 Apr 2016 13:50:54 GMT

Hi,

did you add Caused by: java.lang.ClassNotFoundException: com.stud.service.listener.PrinterListener into the classpath?

Regards
Martin

Re: org.activiti.engine.ActivitiException: couldn't instantiate class com.stud.listener.PrinterListener

natedawg — Mon, 18 Apr 2016 17:49:50 GMT

hi,
yes, PrinterListener is in the classpath. As you can see from the log, all artefacts were able to use this class in the first iteration. however in the second iteration the problem occures. i am not using Spring and ActivitiExplorer is used to execute all processes.

kind regards
A.H.

Re: org.activiti.engine.ActivitiException: couldn't instantiate class com.stud.listener.PrinterListener

martin_grofcik — Tue, 19 Apr 2016 06:57:11 GMT

Hi,

Is it possible to reproduce the issue in the jUnit test?
https://forums.activiti.org/content/sticky-how-write-unit-test

Regards
Martin

Re: org.activiti.engine.ActivitiException: couldn't instantiate class com.stud.listener.PrinterListener

natedawg — Tue, 19 Apr 2016 15:09:33 GMT

Ok but as I mentioned previously, I ran Explorer app to execute the process…

Kind regards
A.H.

Re: org.activiti.engine.ActivitiException: couldn't instantiate class com.stud.listener.PrinterListener

trademak — Wed, 20 Apr 2016 07:05:40 GMT

Hi,

In the BPMN XML you included in your post I don't see an asynchronous task, but the stacktrace mentions the job executor (ExecuteAsyncRunnable) being used. Are you sure you included the correct BPMN XML?
A unit test showing the unit test would still help, also if you are using the Activiti Explorer, because that is also just using the Activiti Engine API.

Best regards,

Re: org.activiti.engine.ActivitiException: couldn't instantiate class com.stud.listener.PrinterListener

natedawg — Wed, 20 Apr 2016 12:12:48 GMT

Hi guys,

I downloaded unit test template and run the test simply by line:
<java>ProcessInstance processInstance = activitiRule.getRuntimeService().startProcessInstanceByKey("ProcDS1");</java>

In the log I see no error but I also notice that only start event and first service task are executed. It means intermediate timer catching event and last service task are never executed (maybe something to do with new thread kicked off by the timer event?).

Here is the zip (just remove .txt as zip-uploads are not allowed), not yet sure this is a bug. Contains activiti-unit-test-template-master and service folders.
Sry, I am not an experienced maven user so just add a classpath ref to service-folder (contains some simple java code executed by service tasks). I did update pom.xml to reflect activiti version I am using (5.19.0.2).

Kind regards
A.H.

Re: org.activiti.engine.ActivitiException: couldn't instantiate class com.stud.listener.PrinterListener

jbarrez — Wed, 20 Apr 2016 14:33:03 GMT

" It means intermediate timer catching event and last service task are never executed"

The reason is because your config does not have the job executor enabled. Once you enable it, timers will be executed.

Re: org.activiti.engine.ActivitiException: couldn't instantiate class com.stud.listener.PrinterListener

natedawg — Thu, 21 Apr 2016 08:21:55 GMT

Hi,

When you say enable JobExecutor you refer to the engine.properties-file in Explorer-app? Like this:
<code>
engine.activate.jobexecutor=true
engine.asyncexecutor.enabled=false
engine.asyncexecutor.activate=false
</code>

If that is the case I can report the same problem occurring when JobExecutor enabled but not all the time, maybe every third time. Ref. Job Executor, in the doc I read that new Async Executor is the preferred one (http://www.activiti.org/userguide/#jobExecutorConfiguration).
According to the same doc JobExecutor is used by default.
Now I tried to enable it specifically in the test project by adding
<code><property name="jobExecutorActivate" value="true" /></code>
in the activiti.cfg.xml
Still the same behavior as previously, last service task is never executed and no exception reported.

Kind regards
A.H.

Re: org.activiti.engine.ActivitiException: couldn't instantiate class com.stud.listener.PrinterListener

natedawg — Thu, 21 Apr 2016 16:57:36 GMT

I found the problem. Before I continue I have to correct my previous post where I stated that after changing engine.activate.jobexecutor=true the process became stable. That was pure luck, first 2/3 runs were successful but after re-running the same process 10-15 times they all failed.

The solution was to add service.jar to activiti-rest lib-folder as well. I thought activiti-explorer and activiti-rest were independent of each other so service.jar was added only to activiti-explorer. I first noticed my process running 100% successfully when I moved activi-explorer to a new Tomcat installation webapps-dir. As soon I added activiti-rest the problem reoccurred. How are those two web apps related besides sharing same DB instance?

Pls, also answer on my previous post where I ask why we should use JobExecutor and not AsyncExecutor in case of the timer? Only one executor at the time is allowed?

Kind regards
A.H.

Re: org.activiti.engine.ActivitiException: couldn't instantiate class com.stud.listener.PrinterListener

trademak — Mon, 25 Apr 2016 07:42:37 GMT

Hi,

The Activiti Explorer and REST webapps are independent yes. But both can have an enabled job executor, so when you enable the job executor on the REST webapp, you'll need the classpath to have all service task classes as well.

Best regards,

Re: org.activiti.engine.ActivitiException: couldn't instantiate class com.stud.listener.PrinterListener

natedawg — Fri, 29 Apr 2016 07:05:35 GMT

Thx for the response Tijs,

Can you pls share some light on JobExecutor vs. AsyncExecutor in case of the timers? Am I absolutely tied to using JobExecutor in case of timers as we can only allow one executor to be enabled in the Explorer?

Kind regards
A.H.

Re: org.activiti.engine.ActivitiException: couldn't instantiate class com.stud.listener.PrinterListener

jbarrez — Tue, 03 May 2016 12:12:27 GMT

"Am I absolutely tied to using JobExecutor in case of timers as we can only allow one executor to be enabled in the Explorer?"

No, you can simply reconfigure the engine to use the Async executor instead of the job executor. Running both is bound to lead to a lot of optimistic locking exceptions.

For timers, there is not that much difference between the two. The performance improvements are generally more in the area of the async executions.

Re: org.activiti.engine.ActivitiException: couldn't instantiate class com.stud.listener.PrinterListener

jbarrez — Tue, 03 May 2016 12:12:52 GMT

See my answer to the duplicate of your question.