activiti-osgi classloader issue

[workflowuser2]

Hi,

I have two bundles :
activiti-osgi-karaf: configures and starts process engine (depends on activiti-osgi)
activiti-osgi-process: contains process.bpmn20.xml, java delegates, process-request bean

reference: activiti-in-action book. java delegates are binded into osgi container as service

process-request bean is a java bean I pass into process variables map:
Map<String, Object> params = new HashMap<String, Object>();
params.put("request", new ProcessRequestBean());
processEngine.getRuntimeService().startProcessInstanceByKey(
            "process", params);

Now, when I try to access ProcessRequestBean into a java delegate:

ProcessRequestBean testPayload = (ProcessRequestBean) execution.getVariable("request");

===
The above works for service tasks.
However, if I put activiti:async="true" in the service task definition, I get the following exception:

Exception in thread "pool-13-thread-3" org.activiti.engine.ActivitiException: coudn't deserialize object in variable 'request'
   at org.activiti.engine.impl.variable.SerializableType.getValue(SerializableType.java:60)
   at org.activiti.engine.impl.persistence.entity.VariableInstanceEntity.getValue(VariableInstanceEntity.java:158)
   at org.activiti.engine.impl.persistence.entity.VariableScopeImpl.getVariable(VariableScopeImpl.java:93)
   at com.acme.workflow.delegates.MyDelegate.execute(DiscoveryHandler.java:20)
   at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
   at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
   at java.lang.reflect.Method.invoke(Method.java:597)
   at org.apache.aries.proxy.impl.ProxyHandler$1.invoke(ProxyHandler.java:50)
   at org.apache.aries.proxy.impl.DefaultWrapper.invoke(DefaultWrapper.java:31)
   at org.apache.aries.proxy.impl.ProxyHandler.invoke(ProxyHandler.java:78)
   at $Proxy67.execute(Unknown Source)

It appears to be classpath/loader issue. In the osgi env, I believe that both engine and process bundles class loaders should be available.

Any help is greatly appreciated.
Activiti newbie

[frederikherema1]

Make sure your ProcessRequestBean implements Serializable. If it's a simple service-task, the process is not persisted and the POJO is still in memory (variable values are cached). Once you have an async, it's serialized to DB and when job-executor does the async work, it's de-serialized again when needed…

If you did implement Serializable, it's indeed an issue with classloading in the job-executor… Can you debug to see what's causing the " org.activiti.engine.ActivitiException: coudn't deserialize object in variable 'request'" in the first place?

[workflowuser2]

Make sure your ProcessRequestBean implements Serializable. If it's a simple service-task, the process is not persisted and the POJO is still in memory (variable values are cached). Once you have an async, it's serialized to DB and when job-executor does the async work, it's de-serialized again when needed…

If you did implement Serializable, it's indeed an issue with classloading in the job-executor… Can you debug to see what's causing the " org.activiti.engine.ActivitiException: coudn't deserialize object in variable 'request'" in the first place?

frederikheremans

ProcessRequestBean does implements Serializable.
When I debugged, the issue appears to be de-serializing the ProcessRequestBean  bytes  from the db.

It appears to be classloader issue. ProcessRequestBean  classloader, is perhaps, not available in the activiti-osgi-karaf bundle.

Do you think the following may help?
http://forums.activiti.org/en/viewtopic.php?f=4&t=1433&start=0

[frederikherema1]

You should try that approach, indeed (setting the class loader).

[workflowuser2]

Hi frederikheremans,

I further looked into this issue and it appears that it might be related to OSGi bundling of activiti-engine.
activiti engine need to allow importing client packages in addition to its own dependencies.

Since these packages/classes are not known during activiti-engine bundle/build time, the MANIFEST.MF file should contain something like below:
DynamicImport-Package: *

I looked at libraries similar to activiti and they use the same mechanism to allow loading client packages.

Let me know your thought and if you want me to test/work on this while I am working on other osgi issues.

activiti newbie

You should try that approach, indeed (setting the class loader).

[frederikherema1]

Yes, this would be good to work on and test to allow cross-bundle imports, not know at build-time.

[rahulkrs]

Did you able to solve this problem? I also got in to a similar issue , when JobExecutor is trying to access the service task which is deployed in a different bundle. I am getting a class not found exception.