Error when claiming a user task

[ganeshr]

Hi,

   I'm getting following error when claiming a task,
       Caused by: org.activiti.engine.ActivitiException: Error while evalutaing expression
        at org.activiti.engine.impl.el.JuelExpression.getValue(JuelExpression.java:59)
        at org.activiti.engine.impl.bpmn.listener.ExpressionTaskListener.notify(ExpressionTaskListener.java:33)
        at org.activiti.engine.impl.delegate.TaskListenerInvocation.invoke(TaskListenerInvocation.java:34)
        at org.activiti.engine.impl.delegate.DelegateInvocation.proceed(DelegateInvocation.java:37)
        at org.activiti.engine.impl.delegate.DefaultDelegateInterceptor.handleInvocation(DefaultDelegateInterceptor.java:25)
        at org.activiti.engine.impl.persistence.entity.TaskEntity.fireEvent(TaskEntity.java:525)
        … 42 more
Caused by: org.activiti.engine.impl.javax.el.ELException: Cannot coerce from class org.activiti.engine.impl.persistence.entity.TaskEntity to interface org.activiti.engine.delegate.DelegateTask
        at org.activiti.engine.impl.juel.TypeConverterImpl.coerceToType(TypeConverterImpl.java:350)
        at org.activiti.engine.impl.juel.TypeConverterImpl.convert(TypeConverterImpl.java:365)
        at org.activiti.engine.impl.juel.ExpressionFactoryImpl.coerceToType(ExpressionFactoryImpl.java:418)
        at org.activiti.engine.impl.javax.el.BeanELResolver.coerceValue(BeanELResolver.java:582)
        at org.activiti.engine.impl.javax.el.BeanELResolver.coerceParams(BeanELResolver.java:574)
        at org.activiti.engine.impl.javax.el.BeanELResolver.invoke(BeanELResolver.java:479)
        at org.activiti.engine.impl.javax.el.CompositeELResolver.invoke(CompositeELResolver.java:397)
        at org.activiti.engine.impl.juel.AstMethod.invoke(AstMethod.java:91)
        at org.activiti.engine.impl.juel.AstMethod.eval(AstMethod.java:75)
        at org.activiti.engine.impl.juel.AstEval.eval(AstEval.java:50)
        at org.activiti.engine.impl.juel.AstNode.getValue(AstNode.java:26)
        at org.activiti.engine.impl.juel.TreeValueExpression.getValue(TreeValueExpression.java:114)
        at org.activiti.engine.impl.delegate.ExpressionGetInvocation.invoke(ExpressionGetInvocation.java:33)
        at org.activiti.engine.impl.delegate.DelegateInvocation.proceed(DelegateInvocation.java:37)
        at org.activiti.engine.impl.delegate.DefaultDelegateInterceptor.handleInvocation(DefaultDelegateInterceptor.java:25)
        at org.activiti.engine.impl.el.JuelExpression.getValue(JuelExpression.java:50)
        … 47 more

   I'm getting the above exception when I place the bpmn specific jar( containing task listener classes) in tomcat/lib folder instead of placing them in activit-explorer/WEB-INF/lib or activit-rest/WEB-INF/lib folder. If jar is placed in activit-explorer/WEB-INF/lib or activit-rest/WEB-INF/lib it is working.
  Is there a way where I can acheive by placing the jar in tomcat lib folder? So that I reduce the overhead of placing the jar in activiti-explorer each time a new version is released.

[jbarrez]

Is there a way where I can acheive by placing the jar in tomcat lib folder? So that I reduce the overhead of placing the jar in activiti-explorer each time a new version is released.

Generally, this is regarded as not a very good practice. The reason is that it can mess up classloaders. I don't know why you see the issue exactly, but it has to do something with those classloaders….

[ganeshr]

The problem is if I place the jar in activiti-explorer/rest  lib folder, then everytime if I want to upgrade to new activiti version, need to take care of placing again business process specific jars in lib folder. Instead I want to place the business process specific jar in common place. So that I need not to worry about whether admin team has taken care of this specific step of placing jars  in activiti apps when upgrade happens. any suggestions?

[frederikherema1]

I'm afraid there is no other way than patching the war with your logic or removing the activiti-*.jar's from the WAR and moving them to the shared-lib folder instead.