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Hi Everyone, I am creating a registration page containing the subject for which a student wants to register for. Workflow looks like: Student visits the Training Event page, the field "Number of Registration" shows the number of students that have registered for the course. Student then selects the course they want to register for. Then they click on registration button. Then a new page shows giving students a "New" button to register for the particular course/training event. Once the New button is clicked >> Trainee /student selects his/ her name with Date. Then Save button is clicked As per expectation the, once Save is clicked a registration is saved into database along with Trainee name and the "Number of Registration" counter should read it from database and counter should be incremented. This is viewed by teacher who is taking the training event.   Note:  Save Button triggers a microflow [ see image ] so that registration is committed into the database. To increment the "Number of Registration" counter it refers the same database.   However while executing the process and clicking on save it give me an error:   When troubleshooting I see below messages in stack trace:   Below is the stack trace for the error: An error has occurred while handling the request. [User 'Anonymous_5028e293-c947-4d08-94ca-fe2187de8827' with session id '8ec3417e-XXXX-XXXX-XXXX-XXXXXXXXd727' and roles 'Administrator'] -------- com.mendix.webui.WebUIException: Exception while executing runtime operation    at com.mendix.webui.actions.client.RuntimeOperationAction.$anonfun$apply$1(RuntimeOperationAction.scala:54) Caused by: com.mendix.modules.microflowengine.MicroflowException: Change object 'Some(TrainingEvent)' should not be null    at MyFirstModule.ACT_Registration_Save (Change : 'Change 'TrainingEvent' (TotalNumberOfRegistrations)') Advanced stacktrace:    at com.mendix.modules.microflowengine.MicroflowUtil.processException(MicroflowUtil.java:83) Caused by: java.lang.IllegalArgumentException: Change object 'Some(TrainingEvent)' should not be null    at com.mendix.modules.microflowengine.actions.mxobject.ChangeAction.execute(ChangeAction.scala:43)    at com.mendix.modules.microflowengine.actions.mxobject.ChangeAction.execute(ChangeAction.scala:12)    at com.mendix.modules.microflowengine.microflow.impl.MicroflowObject.$anonfun$execute$1(MicroflowObject.scala:32)    at scala.Option.flatMap(Option.scala:283)    at com.mendix.modules.microflowengine.microflow.impl.MicroflowObject.execute(MicroflowObject.scala:29)    at com.mendix.modules.microflowengine.microflow.impl.MicroflowImpl.executeAfterBreakingIfNecessary(MicroflowImpl.scala:169)    at com.mendix.modules.microflowengine.microflow.impl.MicroflowImpl.executeAction(MicroflowImpl.scala:116)    at com.mendix.systemwideinterfaces.core.UserAction.execute(UserAction.java:58)    at com.mendix.basis.actionmanagement.CoreActionHandlerImpl.doCall(CoreActionHandlerImpl.scala:71)    at com.mendix.basis.actionmanagement.CoreActionHandlerImpl.call(CoreActionHandlerImpl.scala:48)    at com.mendix.core.actionmanagement.internal.InternalCoreAction.call(InternalCoreAction.java:57)    at com.mendix.basis.actionmanagement.ActionManager.$anonfun$executeSync$2(ActionManager.scala:104)    at com.mendix.util.classloading.Runner$.withContextClassLoader(Runner.scala:20)    at com.mendix.basis.actionmanagement.ActionManager.executeSync(ActionManager.scala:103)    at com.mendix.basis.actionmanagement.MicroflowCallBuilderImpl.execute(MicroflowCallBuilderImpl.scala:62)    at com.mendix.webui.actions.client.MicroflowRuntimeOperationExecutor.runMicroflow(MicroflowRuntimeOperationExecutor.scala:97)    at com.mendix.webui.actions.client.MicroflowRuntimeOperationExecutor.$anonfun$apply$5(MicroflowRuntimeOperationExecutor.scala:57)    at com.mendix.webui.actions.client.RegularClientAction$Helpers$.$anonfun$liftEither$1(RegularClientAction.scala:30)    at com.mendix.webui.actions.client.RegularClientAction$Helpers$StateHandler.$anonfun$apply$4(RegularClientAction.scala:56)    at com.mendix.webui.requesthandling.helpers.StateHandling.withState(StateHandling.scala:46)    at com.mendix.webui.requesthandling.helpers.StateHandling.withState$(StateHandling.scala:43)    at com.mendix.webui.actions.client.RegularClientAction$Helpers$StateHandler.withState(RegularClientAction.scala:46)    at com.mendix.webui.actions.client.RegularClientAction$Helpers$StateHandler.apply(RegularClientAction.scala:54)    at com.mendix.webui.actions.client.RegularClientAction$Helpers$StateHandler.apply(RegularClientAction.scala:46)    at com.mendix.webui.actions.client.MicroflowRuntimeOperationExecutor.apply(MicroflowRuntimeOperationExecutor.scala:58)    at com.mendix.webui.actions.client.RuntimeOperationAction.$anonfun$apply$1(RuntimeOperationAction.scala:49)    at scala.util.Either.flatMap(Either.scala:352)    at com.mendix.webui.actions.client.RuntimeOperationAction.apply(RuntimeOperationAction.scala:33)    at com.mendix.webui.actions.client.RuntimeOperationAction.apply(RuntimeOperationAction.scala:22)    at com.mendix.webui.actions.client.RegularClientAction$Helpers$.$anonfun$liftEither$1(RegularClientAction.scala:30)    at com.mendix.webui.actions.client.RegularClientAction.$anonfun$execute$3(RegularClientAction.scala:120)    at scala.util.Try$.apply(Try.scala:210)    at com.mendix.webui.actions.client.RegularClientAction.$anonfun$execute$2(RegularClientAction.scala:120)    at com.mendix.webui.actions.client.RegularClientAction.$anonfun$execute$2$adapted(RegularClientAction.scala:118)    at com.mendix.webui.requesthandling.helpers.ContextHandling.$anonfun$inContext$7(ContextHandling.scala:58)    at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.scala:18)    at com.mendix.basis.actionmanagement.ActionMonitoring$.$anonfun$monitor$1(ActionMonitoring.scala:52)    at com.mendix.util.classloading.Runner$.withContextClassLoader(Runner.scala:20)    at com.mendix.basis.actionmanagement.ActionMonitoring$.monitor(ActionMonitoring.scala:52)    at com.mendix.webui.requesthandling.helpers.ContextHandling.inContext(ContextHandling.scala:58)    at com.mendix.webui.requesthandling.helpers.ContextHandling.inContext$(ContextHandling.scala:32)    at com.mendix.webui.actions.client.RegularClientAction.inContext(RegularClientAction.scala:94)    at com.mendix.webui.requesthandling.helpers.ContextHandling.inContext(ContextHandling.scala:29)    at com.mendix.webui.requesthandling.helpers.ContextHandling.inContext$(ContextHandling.scala:21)    at com.mendix.webui.actions.client.RegularClientAction.inContext(RegularClientAction.scala:94)    at com.mendix.webui.actions.client.RegularClientAction.$anonfun$execute$1(RegularClientAction.scala:118)    at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.scala:18)    at com.mendix.webui.requesthandling.helpers.ProfileHandling.profileRequest(ProfileHandling.scala:14)    at com.mendix.webui.requesthandling.helpers.ProfileHandling.profileRequest$(ProfileHandling.scala:10)    at com.mendix.webui.actions.client.RegularClientAction.profileRequest(RegularClientAction.scala:94)    at com.mendix.webui.actions.client.RegularClientAction.execute(RegularClientAction.scala:115)    at com.mendix.webui.requesthandling.ClientRequestHandler.handleAction(ClientRequestHandler.scala:96)    at com.mendix.webui.requesthandling.ClientRequestHandler.processRequest(ClientRequestHandler.scala:69)    at com.mendix.externalinterface.connector.RequestHandler.doProcessRequest(RequestHandler.java:37)    at com.mendix.external.connector.MxRuntimeConnector.$anonfun$processRequest$1(MxRuntimeConnector.scala:54)    at com.mendix.external.connector.MxRuntimeConnector.$anonfun$processRequest$1$adapted(MxRuntimeConnector.scala:54)    at com.mendix.util.classloading.Runner$.withContextClassLoader(Runner.scala:20)    at com.mendix.external.connector.MxRuntimeConnector.processRequest(MxRuntimeConnector.scala:54)    at com.mendix.basis.impl.MxRuntimeImpl.processRequest(MxRuntimeImpl.scala:219)    at com.mendix.m2ee.appcontainer.server.handler.RuntimeServlet.service(RuntimeServlet.scala:40)    at javax.servlet.http.HttpServlet.service(HttpServlet.java:750)    at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:764)    at org.eclipse.jetty.servlet.ServletHandler$ChainEnd.doFilter(ServletHandler.java:1665)    at org.eclipse.jetty.websocket.servlet.WebSocketUpgradeFilter.doFilter(WebSocketUpgradeFilter.java:170)    at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:202)    at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1635)    at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:527)    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:221)    at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1570)    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:221)    at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1384)    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:176)    at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:484)    at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1543)    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:174)    at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1306)    at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:129)    at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:122)    at org.eclipse.jetty.server.Server.handle(Server.java:563)    at org.eclipse.jetty.server.HttpChannel.lambda$handle$0(HttpChannel.java:505)    at org.eclipse.jetty.server.HttpChannel.dispatch(HttpChannel.java:762)    at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:497)    at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:282)    at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:314)    at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:100)    at org.eclipse.jetty.io.SelectableChannelEndPoint$1.run(SelectableChannelEndPoint.java:53)    at org.eclipse.jetty.util.thread.strategy.AdaptiveExecutionStrategy.runTask(AdaptiveExecutionStrategy.java:416)    at org.eclipse.jetty.util.thread.strategy.AdaptiveExecutionStrategy.consumeTask(AdaptiveExecutionStrategy.java:385)    at org.eclipse.jetty.util.thread.strategy.AdaptiveExecutionStrategy.tryProduce(AdaptiveExecutionStrategy.java:272)    at org.eclipse.jetty.util.thread.strategy.AdaptiveExecutionStrategy.lambda$new$0(AdaptiveExecutionStrategy.java:140)    at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:411)    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:969)    at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.doRunJob(QueuedThreadPool.java:1194)    at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:1149)    at java.base/java.lang.Thread.run(Thread.java:829)     MicroFlow looks like:     Domain Model Looks like:   Listing the properties of each component of MicroFlow:   1.  2.      3.   4.       5.     6.     Please let me know if there are any suggestions or improvement that I can make to resolve this error.

asked 2024-09-17

4 answers