Unable to init the processEngine correctly

[maurizio_vacca]

Hi all,

in my company we're trying to integrate Activiti inside our web application in order to use it as a workflow manager basically. So I created the diagram and I'm now trying to deploy it and then I added the requested jars inside a WEB-INF's subfolder, including also the activiti.cfg.xml file.
Unfortunately, as soon as I try to initiate a new processEngine an exception occurs and I'm stuck here. The exception thrown is the following:

GRAVE: Servlet.service() for servlet RestServlet threw exception
java.lang.NullPointerException
   at acceleratore.controller.DecController.deployWorkflow(DecController.java:41)
   at acceleratore.components.webservice.rest.DecWorkflowManager.deployWorkflow(DecWorkflowManager.java:19)
   at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
   at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
   at java.lang.reflect.Method.invoke(Unknown Source)
   at com.sun.jersey.spi.container.JavaMethodInvokerFactory$1.invoke(JavaMethodInvokerFactory.java:60)
   at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$TypeOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:185)
   at com.sun.jersey.server.impl.model.method.dispatch.ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:75)
   at com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:302)
   at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
   at com.sun.jersey.server.impl.uri.rules.ResourceClassRule.accept(ResourceClassRule.java:108)
   at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
   at com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:84)
   at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1542)
   at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1473)
   at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1419)
   at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1409)
   at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:409)
   at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:540)
   at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:715)
   at javax.servlet.http.HttpServlet.service(HttpServlet.java:723)
   at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
   at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   at clime.messadmin.filter.MessAdminFilter.doFilter(MessAdminFilter.java:104)
   at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   at acceleratore.controller.http.BalanceFilter.doFilter(BalanceFilter.java:86)
   at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
   at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
   at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
   at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
   at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
   at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
   at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:861)
   at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:606)
   at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
   at java.lang.Thread.run(Unknown Source)
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Here the code for the DecController constructor (notice that the log message "Unable to create the processEngine" is printed as expected before the stack trace)

public DecController(){
      processEngine = ProcessEngines.getDefaultProcessEngine();
      if(processEngine != null){
         logger.debug("Creating new DecController: " + processEngine.getName());
      }
      else{
         logger.error("Unable to create the processEngine");
      }
   }
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Last, the activiti configuration file used (DB references are omitted intentionally here, they're correctly setup in the configuration file).
[blockcode]
<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd" >

  <bean id="processEngineConfiguration" class="org.activiti.engine.impl.cfg.StandaloneProcessEngineConfiguration">
    <property name="databaseType" value="oracle" />
    <property name="jdbcUrl" value="jdbcracle:thin:@xxx.xx.xx.xxx:xxxxrcl" />
    <property name="jdbcDriver" value="oracle.jdbc.OracleDriver" />
    <property name="jdbcUsername" value="xxx" />
    <property name="jdbcPassword" value="xxx" />
   
    <property name="databaseSchemaUpdate" value="true" />
   
    <property name="jobExecutorActivate" value="false" />
   
    <property name="mailServerHost" value="mail.my-corp.com" />
    <property name="mailServerPort" value="5025" />   
  </bean>

</beans>
[/blockcode]
Thanks and Best Regards,

Maurizio

[sathish1]

Try a unit test?? Not sure if the ProcessEngines.Init Method call was done some place else., Am thinking the ProcessEngines is not initialized at all., but a unit tests might do a trick here is a sample code

<link>https://github.com/Activiti/Activiti/blob/7e91e91c080f1cbf274f3f4399670eba488aac1a/modules/activiti-...</link>

Cheers.

[maurizio_vacca]

Thanks for the suggestion! Anyway we figure out that the path for the configuration file was uncorrect and the file was not loaded correctly. We moved to a folder included in the build path and now the processEngine starts correctly.

Best Regards!