Generic UI Screen Issues

I have entities that are organized in a combined inheritance/composition structure. I have an Entity ProdPackage2 that has several PackVersions. Each ProdPackage2 can be an instance of one of three sub-classes (Plastic, Cerdip, OpenCavity). Each PackVersion can be an instance ofone of three sub-classes (PlasticVersion, CerdipVersion, or openCavityVersion). I have generic screens for each of these entities. The screens for the sub-classes all appear to be working correctly. But when I generate screens for ProdPackage2 and PackVersion things get weird. The ProdPackage2 browser screen (unchanged from the default, generated screen) shows no entities. I am looking at the data from this table in a console connected to my postgres server so I know it is there. But it doesn’t show up at all in the browser screen. For the PackVersion, The filter can return 50 or 500 rows but when I try to request 100 rows it throws an exception:

java.lang.NullPointerException
	at java.util.ArrayList.<init>(ArrayList.java:177)
	at org.eclipse.persistence.mappings.ForeignReferenceMapping.prepareNestedJoinQueryClone(ForeignReferenceMapping.java:2452)
	at org.eclipse.persistence.mappings.OneToOneMapping.valueFromRowInternalWithJoin(OneToOneMapping.java:1818)
	at org.eclipse.persistence.mappings.ForeignReferenceMapping.valueFromRow(ForeignReferenceMapping.java:2170)
	at org.eclipse.persistence.mappings.ForeignReferenceMapping.buildCloneFromRow(ForeignReferenceMapping.java:336)
	at org.eclipse.persistence.mappings.ForeignReferenceMapping.buildCloneFromRow(ForeignReferenceMapping.java:359)
	at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildAttributesIntoWorkingCopyClone(ObjectBuilder.java:1997)
	at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildWorkingCopyCloneFromRow(ObjectBuilder.java:2258)
	at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildObjectInUnitOfWork(ObjectBuilder.java:848)
	at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildObject(ObjectBuilder.java:735)
	at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildObject(ObjectBuilder.java:689)
	at org.eclipse.persistence.queries.ObjectLevelReadQuery.buildObject(ObjectLevelReadQuery.java:802)
	at org.eclipse.persistence.queries.ReadAllQuery.registerResultInUnitOfWork(ReadAllQuery.java:962)
	at org.eclipse.persistence.queries.ReadAllQuery.executeObjectLevelReadQuery(ReadAllQuery.java:573)
	at org.eclipse.persistence.queries.ObjectLevelReadQuery.executeDatabaseQuery(ObjectLevelReadQuery.java:1172)
	at org.eclipse.persistence.queries.DatabaseQuery.execute(DatabaseQuery.java:904)
	at org.eclipse.persistence.queries.ObjectLevelReadQuery.execute(ObjectLevelReadQuery.java:1131)
	at org.eclipse.persistence.queries.ReadAllQuery.execute(ReadAllQuery.java:460)
	at org.eclipse.persistence.queries.ObjectLevelReadQuery.executeInUnitOfWork(ObjectLevelReadQuery.java:1219)
	at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.internalExecuteQuery(UnitOfWorkImpl.java:2944)
	at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1854)
	at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1836)
	at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1801)
	at org.eclipse.persistence.internal.jpa.QueryImpl.executeReadQuery(QueryImpl.java:258)
	at org.eclipse.persistence.internal.jpa.QueryImpl.getResultList(QueryImpl.java:473)
	at com.haulmont.cuba.core.sys.QueryImpl.getResultFromCache(QueryImpl.java:658)
	at com.haulmont.cuba.core.sys.QueryImpl.getResultList(QueryImpl.java:342)
	at com.haulmont.cuba.core.app.RdbmsStore.executeQuery(RdbmsStore.java:703)
	at com.haulmont.cuba.core.app.RdbmsStore.getResultList(RdbmsStore.java:611)
	at com.haulmont.cuba.core.app.RdbmsStore.loadList(RdbmsStore.java:210)
	at com.haulmont.cuba.core.app.DataManagerBean.loadList(DataManagerBean.java:84)
	at sun.reflect.GeneratedMethodAccessor256.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at com.haulmont.cuba.core.app.DataManagerBean$SecureDataManagerInvocationHandler.invoke(DataManagerBean.java:362)
	at com.sun.proxy.$Proxy322.loadList(Unknown Source)
	at com.haulmont.cuba.core.app.DataServiceBean.loadList(DataServiceBean.java:51)
	at sun.reflect.GeneratedMethodAccessor255.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:333)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:190)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
	at org.springframework.aop.aspectj.MethodInvocationProceedingJoinPoint.proceed(MethodInvocationProceedingJoinPoint.java:85)
	at com.haulmont.cuba.core.sys.ServiceInterceptor.aroundInvoke(ServiceInterceptor.java:117)
	at sun.reflect.GeneratedMethodAccessor179.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethodWithGivenArgs(AbstractAspectJAdvice.java:629)
	at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethod(AbstractAspectJAdvice.java:618)
	at org.springframework.aop.aspectj.AspectJAroundAdvice.invoke(AspectJAroundAdvice.java:70)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:168)
	at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213)
	at com.sun.proxy.$Proxy219.loadList(Unknown Source)
	at sun.reflect.GeneratedMethodAccessor254.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at com.haulmont.cuba.core.sys.remoting.LocalServiceInvokerImpl.invoke(LocalServiceInvokerImpl.java:94)
	at com.haulmont.cuba.web.sys.remoting.LocalServiceProxy$LocalServiceInvocationHandler.invoke(LocalServiceProxy.java:154)
	at com.sun.proxy.$Proxy29.loadList(Unknown Source)
	at com.haulmont.cuba.client.sys.DataManagerClientImpl.loadList(DataManagerClientImpl.java:53)
	at com.haulmont.cuba.gui.data.impl.GenericDataSupplier.loadList(GenericDataSupplier.java:102)
	at com.haulmont.cuba.gui.data.impl.CollectionDatasourceImpl.loadData(CollectionDatasourceImpl.java:613)
	at com.haulmont.cuba.gui.data.impl.CollectionDatasourceImpl.refresh(CollectionDatasourceImpl.java:161)
	at com.haulmont.cuba.gui.data.impl.CollectionDatasourceImpl.refreshIfNotSuspended(CollectionDatasourceImpl.java:112)
	at com.haulmont.cuba.gui.components.filter.FilterDelegateImpl.refreshDatasource(FilterDelegateImpl.java:1643)
	at com.haulmont.cuba.gui.components.filter.FilterDelegateImpl.apply(FilterDelegateImpl.java:1487)
	at com.haulmont.cuba.gui.components.filter.FilterDelegateImpl$1.actionPerform(FilterDelegateImpl.java:288)
	at com.haulmont.cuba.web.gui.components.WebButton.performAction(WebButton.java:45)
	at com.haulmont.cuba.web.gui.components.WebButton.lambda$new$61446b05$1(WebButton.java:37)
	at sun.reflect.GeneratedMethodAccessor364.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at com.vaadin.event.ListenerMethod.receiveEvent(ListenerMethod.java:510)
	at com.vaadin.event.EventRouter.fireEvent(EventRouter.java:200)
	at com.vaadin.event.EventRouter.fireEvent(EventRouter.java:163)
	at com.vaadin.server.AbstractClientConnector.fireEvent(AbstractClientConnector.java:1037)
	at com.vaadin.ui.Button.fireClick(Button.java:377)
	at com.haulmont.cuba.web.toolkit.ui.CubaButton.fireClick(CubaButton.java:54)
	at com.vaadin.ui.Button$1.click(Button.java:54)
	at sun.reflect.GeneratedMethodAccessor363.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at com.vaadin.server.ServerRpcManager.applyInvocation(ServerRpcManager.java:158)
	at com.vaadin.server.ServerRpcManager.applyInvocation(ServerRpcManager.java:119)
	at com.vaadin.server.communication.ServerRpcHandler.handleInvocation(ServerRpcHandler.java:444)
	at com.vaadin.server.communication.ServerRpcHandler.handleInvocations(ServerRpcHandler.java:409)
	at com.vaadin.server.communication.ServerRpcHandler.handleRpc(ServerRpcHandler.java:274)
	at com.vaadin.server.communication.UidlRequestHandler.synchronizedHandleRequest(UidlRequestHandler.java:90)
	at com.vaadin.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:41)
	at com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1435)
	at com.vaadin.server.VaadinServlet.service(VaadinServlet.java:361)
	at com.haulmont.cuba.web.sys.CubaApplicationServlet.serviceAppRequest(CubaApplicationServlet.java:312)
	at com.haulmont.cuba.web.sys.CubaApplicationServlet.service(CubaApplicationServlet.java:203)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.springframework.web.filter.CompositeFilter$VirtualFilterChain.doFilter(CompositeFilter.java:107)
	at org.springframework.web.filter.CompositeFilter.doFilter(CompositeFilter.java:73)
	at com.haulmont.cuba.web.sys.CubaHttpFilter.doFilter(CubaHttpFilter.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:198)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80)
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:624)
	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:799)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:861)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1455)
	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:748)

I’m not sure if this is just a fluke or what. I would make a zipProject for you but I’m not sure you want to see the full scale project that I’ve been working on. I’m using platform version 6.9.3

It can be a bug or something in EclipseLink.
In order to fix it or suggest a workaround, we need a test project with minimal code where the problem is reproduced.

It turned out to be an issue with the fetch type on a view. I specified it as a JOIN and that seems to be what broke it.

Thank you for letting us know.
Fetch mode can really break a complex query. AUTO usually works fine, but if something weird happens, try
UNDEFINED - it’s the most safe mode because the reference is fetched with a separate select.