Got UnsupportOperationException when executing a work item - drools

Question

I have already registered a work item in a project on drools workbench (version 7.16.0.Final). What I am doing is to execute this work item in a guide decision table.
I can see that the work item is executed when the condition is matched, but don't have a clue why this exception thrown.
2019-01-22 17:22:30.014 [http-nio-9043-exec-3] ERROR o.a.c.c.C.[.[.[.[dispatcherServlet] - Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is Exception executing consequence for rule "Row 2 decisiontable" in com.myproj.cdi: [Error: wim.internalExecuteWorkItem( wiQianhaiAddrWorkItemHandler ): null]
[Near : {... org.drools.core.process.instan ....}]
^
[Line: 1, Column: 1]] with root cause
java.lang.UnsupportedOperationException: null
at org.drools.core.impl.StatefulKnowledgeSessionImpl$DummyInternalProcessRuntime.getProcessInstance(StatefulKnowledgeSessionImpl.java:2223)
at org.drools.core.impl.StatefulKnowledgeSessionImpl.getProcessInstance(StatefulKnowledgeSessionImpl.java:1884)
at org.drools.core.process.instance.impl.DefaultWorkItemManager.completeWorkItem(DefaultWorkItemManager.java:142)
at com.myproj.group.digital.cdi.QianhaiAddrWorkItemHandler.executeWorkItem(QianhaiAddrWorkItemHandler.java:32)
at org.drools.core.process.instance.impl.DefaultWorkItemManager.internalExecuteWorkItem(DefaultWorkItemManager.java:71)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.getMethod(ReflectiveAccessorOptimizer.java:1119)
at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.getMethod(ReflectiveAccessorOptimizer.java:1002)
at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.compileGetChain(ReflectiveAccessorOptimizer.java:396)
at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.optimizeAccessor(ReflectiveAccessorOptimizer.java:163)
at org.mvel2.ast.ASTNode.optimize(ASTNode.java:159)
at org.mvel2.ast.ASTNode.getReducedValueAccelerated(ASTNode.java:115)
at org.mvel2.MVELRuntime.execute(MVELRuntime.java:85)
at org.mvel2.compiler.CompiledExpression.getDirectValue(CompiledExpression.java:123)
at org.mvel2.compiler.CompiledExpression.getValue(CompiledExpression.java:119)
at org.mvel2.compiler.CompiledExpression.getValue(CompiledExpression.java:113)
at org.mvel2.MVEL.executeExpression(MVEL.java:929)
at org.drools.core.base.mvel.MVELConsequence.evaluate(MVELConsequence.java:110)
at org.drools.core.phreak.RuleExecutor.innerFireActivation(RuleExecutor.java:431)
at org.drools.core.phreak.RuleExecutor.fireActivation(RuleExecutor.java:379)
at org.drools.core.phreak.RuleExecutor.fire(RuleExecutor.java:135)
at org.drools.core.phreak.RuleExecutor.evaluateNetworkAndFire(RuleExecutor.java:88)
at org.drools.core.concurrent.AbstractRuleEvaluator.internalEvaluateAndFire(AbstractRuleEvaluator.java:34)
at org.drools.core.concurrent.SequentialRuleEvaluator.evaluateAndFire(SequentialRuleEvaluator.java:43)
at org.drools.core.common.DefaultAgenda.fireLoop(DefaultAgenda.java:1066)
at org.drools.core.common.DefaultAgenda.internalFireAllRules(DefaultAgenda.java:1013)
at org.drools.core.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1005)
at org.drools.core.impl.StatefulKnowledgeSessionImpl.internalFireAllRules(StatefulKnowledgeSessionImpl.java:1330)
at org.drools.core.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:1321)
at org.drools.core.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:1305)
at com.group.myproj.digital.cdi.decision.engine.service.CdiKieWbService.checkAddress(CdiKieWbService.java:57)
at com.group.myproj.digital.cdi.decision.engine.controller.ApsKieController.checkAddressValidity(ApsKieController.java:63)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:870)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:776)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:978)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:881)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:661)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:855)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:496)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:790)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
This is the java code snippet I am using to execute the rules defined in decision table.
KieServices ks = KieServices.Factory.get();
ReleaseId releaseId = ks.newReleaseId("com.myproj.poc", "cdi", "1.0.0");
KieContainer kContainer = ks.newKieContainer(releaseId);
KieScanner kScanner = ks.newKieScanner(kContainer);
kScanner.scanNow();
KieSession kSession = kContainer.newKieSession("cdiStatefulKieSession");
kSession.insert(request);
kSession.fireAllRules();
No idea why the DummyInternalProcessRuntime is invoked. Can anyone give a hint ?
Following Tibor's suggestion. I have replaced Drools workbench with jBPM and added the jBPM dependencies in my java project. However, this time I got another exception .
2019-01-24 13:53:53.865 [http-nio-9043-exec-2] ERROR o.a.c.c.C.[.[.[.[dispatcherServlet] - Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Handler dispatch failed; nested exception is java.lang.ExceptionInInitializerError] with root cause
java.lang.ClassCastException: org.jbpm.assembler.BPMN2AssemblerService cannot be cast to org.kie.api.internal.assembler.KieAssemblerService
at org.kie.internal.services.KieAssemblersImpl.accept(KieAssemblersImpl.java:31)
at org.kie.api.internal.utils.ServiceDiscoveryImpl.buildMap(ServiceDiscoveryImpl.java:174)
at org.kie.api.internal.utils.ServiceDiscoveryImpl.getServices(ServiceDiscoveryImpl.java:97)
at org.kie.api.internal.utils.ServiceRegistryImpl.<init>(ServiceRegistryImpl.java:36)
at org.kie.api.internal.utils.ServiceRegistryImpl$LazyHolder.<clinit>(ServiceRegistryImpl.java:32)
at org.kie.api.internal.utils.ServiceRegistry.getInstance(ServiceRegistry.java:27)
at org.kie.api.KieServices$Factory$LazyHolder.<clinit>(KieServices.java:341)
at org.kie.api.KieServices$Factory.get(KieServices.java:348)
Here are the dependencies in pom.xml.
<dependency>
<groupId>org.kie</groupId>
<artifactId>kie-api</artifactId>
</dependency>
<dependency>
<groupId>org.kie</groupId>
<artifactId>kie-ci</artifactId>
</dependency>
<dependency>
<groupId>org.drools</groupId>
<artifactId>drools-core</artifactId>
</dependency>
<dependency>
<groupId>org.drools</groupId>
<artifactId>drools-compiler</artifactId>
</dependency>
<dependency>
<groupId>org.drools</groupId>
<artifactId>drools-decisiontables</artifactId>
</dependency>
<dependency>
<groupId>org.drools</groupId>
<artifactId>drools-workbench-models-guided-dtable</artifactId>
</dependency>
<dependency>
<groupId>org.jbpm</groupId>
<artifactId>jbpm-flow</artifactId>
</dependency>
<dependency>
<groupId>org.jbpm</groupId>
<artifactId>jbpm-flow-builder</artifactId>
</dependency>
<dependency>
<groupId>org.jbpm</groupId>
<artifactId>jbpm-bpmn2</artifactId>
</dependency>
<dependency>
<groupId>org.jbpm</groupId>
<artifactId>jbpm-persistence-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.jbpm</groupId>
<artifactId>jbpm-human-task-core</artifactId>
</dependency>
<dependency>
<groupId>org.jbpm</groupId>
<artifactId>jbpm-runtime-manager</artifactId>
</dependency>
<dependency>
<groupId>org.jbpm</groupId>
<artifactId>jbpm-executor</artifactId>
</dependency>
<dependency>
<groupId>org.jbpm</groupId>
<artifactId>jbpm-kie-services</artifactId>
</dependency>
<dependency>
<groupId>org.jbpm</groupId>
<artifactId>jbpm-services-api</artifactId>
</dependency>
The Kie server shows that BPM is already in capabilities. When access http://localhost:8080/kie-server/services/rest/server I an see the response as following.
<response type="SUCCESS" msg="Kie Server info">
<kie-server-info>
<capabilities>KieServer</capabilities>
<capabilities>BRM</capabilities>
<capabilities>BPM</capabilities>
<capabilities>CaseMgmt</capabilities>
<capabilities>BPM-UI</capabilities>
<capabilities>BRP</capabilities>
<capabilities>DMN</capabilities>
<capabilities>Swagger</capabilities>
<location>
http://localhost:8080/kie-server/services/rest/server
</location>
<messages>
<content>
Server KieServerInfo{serverId='sample-server', version='7.16.0.Final', name='sample-server', location='http://localhost:8080/kie-server/services/rest/server', capabilities=[KieServer, BRM, BPM, CaseMgmt, BPM-UI, BRP, DMN, Swagger], messages=null}started successfully at Sat Jan 26 17:15:20 CST 2019
</content>
<severity>INFO</severity>
<timestamp>2019-01-26T17:15:20.444+08:00</timestamp>
</messages>
<name>sample-server</name>
<id>sample-server</id>
<version>7.16.0.Final</version>
</kie-server-info>
</response>

Answer 1

Looks like you don't have jBPM dependencies in your project. jBPM is a process runtime. When not having it on classpath, Drools uses a dummy process runtime for handling processes (and therefore workitems) which doesn't support all possible operations - therefore the exception you see. If you use just Drools workbench now, please use jBPM workbench [1], which is basically the same thing, just with process capabilities as an extra (jBPM bundled in). jBPM project is a project from the same community projects group (KieGroup) as is Drools.
[1] http://jbpm.org/download/download.html

Answer 2

Can you describe your use case a little bit more? How exactly did you register a work item handler in drools-wb because there is no such feature in drools-wb. Work item handlers are used in case you have a process and it has a node of a certain type which will be handled by a work item handler. In case you have your facts and your rules in decision table, you shouldn't need any work item handlers to fire these rules.
Update:
Sorry, yes, you can use work item handlers in decision tables nowadays.
Here is the configuration which is working for our tests:
kie-deployment-descriptor.xml
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<deployment-descriptor xsi:schemaLocation="http://www.jboss.org/jbpm deployment-descriptor.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<persistence-unit>org.jbpm.domain</persistence-unit>
<audit-persistence-unit>org.jbpm.domain</audit-persistence-unit>
<audit-mode>JPA</audit-mode>
<persistence-mode>JPA</persistence-mode>
<runtime-strategy>SINGLETON</runtime-strategy>
<marshalling-strategies/>
<event-listeners/>
<task-event-listeners/>
<globals/>
<work-item-handlers>
<work-item-handler>
<resolver>mvel</resolver>
<identifier>new org.jbpm.process.workitem.bpmn2.ServiceTaskHandler(ksession, classLoader)</identifier>
<parameters/>
<name>Service Task</name>
</work-item-handler>
<work-item-handler>
<resolver>mvel</resolver>
<identifier>new org.jbpm.process.instance.impl.demo.SystemOutWorkItemHandler()</identifier>
<parameters/>
<name>Log</name>
</work-item-handler>
<work-item-handler>
<resolver>mvel</resolver>
<identifier>new org.jbpm.process.workitem.webservice.WebServiceWorkItemHandler(ksession, classLoader)</identifier>
<parameters/>
<name>WebService</name>
</work-item-handler>
<work-item-handler>
<resolver>mvel</resolver>
<identifier>new org.jbpm.process.workitem.rest.RESTWorkItemHandler()</identifier>
<parameters/>
<name>Rest</name>
</work-item-handler>
<work-item-handler>
<resolver>reflection</resolver>
<identifier>new org.jboss.qa.brms.workitems.ResultWIHandler()</identifier>
<parameters/>
<name>ResultWI</name>
</work-item-handler>
<work-item-handler>
<resolver>reflection</resolver>
<identifier>new org.jboss.qa.brms.workitems.SimpleWIHandler()</identifier>
<parameters/>
<name>SimpleWI</name>
</work-item-handler>
</work-item-handlers>
<environment-entries/>
<configurations/>
<required-roles/>
<remoteable-classes/>
</deployment-descriptor>
So we have ResultWI and SimpleWI WIHs registered.
Now kmodule.xml:
<kmodule xmlns="http://jboss.org/kie/6.0.0/kmodule" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<kbase name="kbase1" default="true" eventProcessingMode="stream" equalsBehavior="identity">
<ksession name="ksession" type="stateful" default="true" clockType="realtime">
<workItemHandlers>
<workItemHandler type="org.jboss.qa.brms.workitems.ResultWIHandler" name="ResultWI"/>
<workItemHandler type="org.jboss.qa.brms.workitems.SimpleWIHandler" name="SimpleWI"/>
</workItemHandlers>
</ksession>
</kbase>
<kbase name="defaultKieBase" default="false" eventProcessingMode="stream" equalsBehavior="identity"/>
</kmodule>
And finally WID files:
resultWID.wid
import org.drools.core.process.core.datatype.impl.type.StringDataType;
import org.drools.core.process.core.datatype.impl.type.ObjectDataType;
[
[
"name" : "ResultWI",
"parameters" : [
"value" : new StringDataType()
],
"results" : [
"result" : new StringDataType()
],
"displayName" : "ResultWI"
]
]
simpleWID.wid
import org.drools.core.process.core.datatype.impl.type.StringDataType;
[
[
"name" : "SimpleWI",
"parameters" : [
"value" : new StringDataType()
],
"displayName" : "SimpleWI"
]
]
Can you verify that you have similar configuration? In case it still doesn't work, try turning on jBPM capabilities on your KIE Server. And you don't have to include jbpm dependencies on your classpath since your deployment runs inside KIE Server where all dependencies are available. I hope that helps.