Drools – gets the Java. DLL when the activate method is called on the taskclient lang.NullPointerException

Exception getting null pointer when calling activate method on client object This is my code

@RequestMapping(value="/loanreq",method=RequestMethod.GET)
  public String loanRequest(HttpServletRequest req,HttpSession session) throws DroolsParserException,IOException,NamingException{

   StatefulKNowledgeSession ksession = processEngine.getKsession();

   ksession.getWorkItemManager().registerWorkItemHandler("Human Task",new WSHumanTaskHandler());

   TaskClient client = new TaskClient(new MinaTaskClientConnector("UserTask",new MinaTaskClientHandler(SystemEventListenerFactory.getSystemEventListener())));

        client.connect("ipaddress",9123);
        BlockingTaskOperationResponseHandler responseHandler =

                new BlockingTaskOperationResponseHandler();
        client.activate(3,"krisv",responseHandler);

        client.start(3,responseHandler);

            client.complete( 3,null,responseHandler );




   Map<String,Object> params=new HashMap();
   params.put("employee","krisv");


   ProcessInstance processInstance =ksession.startProcess("com.vr.controller2",params); 


   System.out.println("id is "+processInstance.getId());

   return "return1";
  }

I get the following exceptions

java.lang.NullPointerException
at org.jbpm.task.service.mina.MinaTaskClientConnector.write(MinaTaskClientConnector.java:118)
at org.jbpm.task.service.TaskClient.activate(TaskClient.java:651)
at com.vr.controller.hellocontroller.loanRequest(hellocontroller.java:181)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:212)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:126)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:96)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:617)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:578)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:900)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:827)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:778)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:311)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:116)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:83)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:101)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:54)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:150)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:182)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
at org.springframework.security.web.authentication.logout.logoutFilter.doFilter(logoutFilter.java:105)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:173)
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:259)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1041)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:603)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)

I saw the client object while debugging, but it is not null I don't know why I received this error I received this error on the "client. Activate()" line instead of "client. Connect()"

Solution

According to the stack trace, this error occurs because the session in minataskclientconnector is empty As far as I know, the source codes are taskclient and minataskclientconnector because the connect method fails. In this Code:

try {
      connector.getFilterChain().addLast("codec",new ProtocolCodecFilter(new ObjectSerializationCodecFactory()));

      ConnectFuture future1 = connector.connect( address );
      future1.awaitUninterruptibly();
      if (!future1.isConnected()) {
          return false;
      }
      session = future1.getSession();
      return true;
 } catch (Exception e) {
      logger.error(e.getMessage(),e);
      return false;
 }

You can find the exact error in the log or place a breakpoint in the catch block

In addition, I recommend checking the result of the connect method (which returns a Boolean value to indicate that the connection was successful) and doing the following:

if (client.connect("ipaddress",9123) {
      BlockingTaskOperationResponseHandler responseHandler = new BlockingTaskOperationResponseHandler();
      client.activate(3,responseHandler);
      client.start(3,responseHandler);
      client.complete( 3,responseHandler );
      Map<String,Object> params=new HashMap();
      params.put("employee","krisv");
      ProcessInstance processInstance =ksession.startProcess("com.vr.controller2",params); 
      System.out.println("id is "+processInstance.getId());
      return "return1";
} else {
      //TODO code to report connection error
}