Issue #544: NullPointer when accessing persistent field

I am afraid this is a large and complex example, and I do not encounter the problem in simple cases, therefore there is no example attached. I appreciate this may make the bug unreproduceable from your end.

[ObjectDB 2.3.2] Unexpected exception (Error 990)
  Generated by Java HotSpot(TM) Server VM 1.6.0_27 (on Windows Server 2008 6.0).
Please report this error on http://www.objectdb.com/database/issue/new
com.objectdb.o.InternalException: java.lang.NullPointerException: null
java.lang.NullPointerException
at com.objectdb.o.ISP.size(ISP.java:153)
at com.objectdb.o.CLT.visitRefs(CLT.java:156)
at com.objectdb.o.TVS.j(TVS.java:169)
at com.objectdb.o.TVS.cascade(TVS.java:156)
at com.objectdb.o.STA.Q(STA.java:476)
at com.objectdb.o.STM.D(STM.java:390)
at com.objectdb.o.OBM.bJ(OBM.java:884)
at com.objectdb.jdo.PMImpl.bJ(PMImpl.java:2186)
at com.objectdb.o.OBM.bI(OBM.java:800)
at com.objectdb.o.OBM.bH(OBM.java:750)
at com.objectdb.o.QRR.b(QRR.java:137)
at com.objectdb.o.QRR.b(QRR.java:634)
at com.objectdb.o.UMR.u(UMR.java:501)
at com.objectdb.o.ENT.loadInverse(ENT.java:1284)
at com.objectdb.o.IVP.g(IVP.java:96)
at com.objectdb.o.IVP.f(IVP.java:83)
at com.objectdb.o.ISP.iterator(ISP.java:126)
at java.util.Collections$UnmodifiableCollection$1.<init>(Collections.java:1007)
at java.util.Collections$UnmodifiableCollection.iterator(Collections.java:1006)
at com.aqera.utilitymanager.scheme.tasks.ActivityWait.execute_Completion(ActivityWait.java:748)
at com.aqera.utilitymanager.scheme.tasks.ActivityWait.execute_D1(ActivityWait.java:712)
at com.aqera.utilitymanager.scheme.tasks.ActivityWait.end_AwaitOutCome(ActivityWait.java:789)
at com.aqera.utilitymanager.scheme.tasks.ActivityWait.receiveEvent_Completion(ActivityWait.java:639)
at com.aqera.utilitymanager.scheme.tasks.ActivityWait.generateCallEvent(ActivityWait.java:585)
at com.aqera.utilitymanager.scheme.tasks.ActivityWait.completionSignal(ActivityWait.java:524)
at com.aqera.utilitymanager.scheme.tasks.ActivityWait.z_completion(ActivityWait.java:352)
at com.aqera.utilitymanager.scheme.tasks.ActivityWait.completion(ActivityWait.java:367)
at com.aqera.utilitymanager.scheme.tasks.RegisterActivity.z_receiveWaitingNotification(RegisterActivity.java:421)
at com.aqera.utilitymanager.scheme.tasks.RegisterActivity.receiveWaitingNotification(RegisterActivity.java:439)
at com.aqera.utilitymanager.scheme.registers.UtilityServicesSingleton.z_activityWaitingNotification(UtilityServicesSingleton.java:1174)
at com.aqera.utilitymanager.scheme.registers.UtilityServicesSingleton.activityWaitingNotification(UtilityServicesSingleton.java:1206)
at com.aqera.utilitymanager.scheme.services.myservices.UtilityActivityServicesBeanImpl.z_activityWaitingNotification(UtilityActivityServicesBeanImpl.java:160)
at com.aqera.utilitymanager.scheme.services.myservices.UtilityActivityServicesBeanImpl.activityWaitingNotification(UtilityActivityServicesBeanImpl.java:149)
at com.aqera.domains.jurisdiction.registers.Jurisdiction.execute_StartRegulatedScheme(Jurisdiction.java:1489)
at com.aqera.domains.jurisdiction.registers.Jurisdiction.execute_M3(Jurisdiction.java:1332)
at com.aqera.domains.jurisdiction.registers.Jurisdiction.end_JurisdictionEstablished(Jurisdiction.java:1551)
at com.aqera.domains.jurisdiction.registers.Jurisdiction.receiveEvent_StartRegulatedScheme(Jurisdiction.java:1245)
at com.aqera.domains.jurisdiction.services.testing.SchemeRegisterTestingServiceBeanImpl.z_createSchemeInJurisdiction(SchemeRegisterTestingServiceBeanImpl.java:55)
at com.aqera.domains.jurisdiction.services.testing.SchemeRegisterTestingServiceBeanImpl.createSchemeInJurisdiction(SchemeRegisterTestingServiceBeanImpl.java:38)
at com.aqera.domains.one.tests.InitializationTest.testCreateSchemeAndRegister(InitializationTest.java:126)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at junit.framework.TestCase.runTest(TestCase.java:164)
at junit.framework.TestCase.runBare(TestCase.java:130)
at com.aqera.domains.one.tests.InitializationTest.runBare(InitializationTest.java:31)
at junit.framework.TestResult$1.protect(TestResult.java:106)
at junit.framework.TestResult.runProtected(TestResult.java:124)
at junit.framework.TestResult.run(TestResult.java:109)
at junit.framework.TestCase.run(TestCase.java:120)
at junit.framework.TestSuite.runTest(TestSuite.java:230)
at junit.framework.TestSuite.run(TestSuite.java:225)
at junit.framework.TestSuite.runTest(TestSuite.java:230)
at junit.framework.TestSuite.run(TestSuite.java:225)
at com.aqera.domains.one.tests.SimulatorTestSuite$1.run(SimulatorTestSuite.java:60)
at org.eclipse.jdt.internal.junit.runner.junit3.JUnit3TestReference.run(JUnit3TestReference.java:130)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

If the stack trace is no use I can send a zip of the entire example, which runs from the command line under maven ( I will have to send you a snapshot of some of the utility dependencies )

The code being called is accessing a map declared as follows;

@OneToMany(cascade=CascadeType.ALL, mappedBy="z_component")
@MapKey(name="z_schemeName")
    private java.util.Map<java.lang.String, com.aqera.domains.jurisdiction.regulatedschemes.RegulatedScheme> z_regulatedSchemes  = new java.util.HashMap<java.lang.String, com.aqera.domains.jurisdiction.regulatedschemes.RegulatedScheme>();

I have attached the log and db files ( transaction is rolled back )

The packages were all enhanced ( static weaving ).

The following test case reproduces the exception. It may be thrown on accessing an inverse collection in an entity that has been garbage collected. Build 2.3.2_01 fixes it (at least this test case works now).

import java.util.List;

import javax.persistence.*;

public class T544 {
   
    public static void main(String[] args) {

        EntityManagerFactory emf =
            Persistence.createEntityManagerFactory(
                "objectdb:$objectdb/db/test.tmp;drop");

        EntityManager em = emf.createEntityManager();
        em.getTransaction().begin();
        A a = new A();
        B b = new B();
        b.a = a;
        em.persist(a);
        em.persist(b);
        em.getTransaction().commit();
        em.close();

        em = emf.createEntityManager();
        a = em.createQuery("SELECT a FROM A a", A.class).getSingleResult();
        List<B> list = a.list;
        a = null;
        System.gc();
        System.out.println(list.size());
        em.close();

        emf.close();
    }

    @Entity
    public static class A {
        @OneToMany(targetEntity = B.class, mappedBy = "a")
        private List<B> list;
    }

    @Entity
    public static class B {
        A a;
    }
}

Kudos! Thanks.

I no longer have that problem, but a Type not found 301 error, and will implement workaround for that and let you know.

Unfortunately I have a similar problem, now I have passed the type 301 error.

[ObjectDB 2.3.2_01] Unexpected exception (Error 990)
  Generated by Java HotSpot(TM) Server VM 1.6.0_27 (on Windows Server 2008 6.0).
Please report this error on http://www.objectdb.com/database/issue/new
com.objectdb.o.InternalException: java.lang.NullPointerException: null
java.lang.NullPointerException
at com.objectdb.o.ISP.size(ISP.java:153)
at com.objectdb.o.CLT.visitRefs(CLT.java:156)
at com.objectdb.o.TVS.j(TVS.java:169)
at com.objectdb.o.TVS.cascade(TVS.java:156)
at com.objectdb.o.STA.Q(STA.java:476)
at com.objectdb.o.STM.D(STM.java:390)
at com.objectdb.o.OBM.bJ(OBM.java:884)
at com.objectdb.jdo.PMImpl.bJ(PMImpl.java:2186)
at com.objectdb.o.OBM.bI(OBM.java:800)
at com.objectdb.o.OBM.bH(OBM.java:750)
at com.objectdb.o.QRR.b(QRR.java:137)
at com.objectdb.o.QRR.b(QRR.java:634)
at com.objectdb.o.UMR.u(UMR.java:501)
at com.objectdb.o.ENT.loadInverse(ENT.java:1284)
at com.objectdb.o.IVP.h(IVP.java:100)
at com.objectdb.o.IVP.g(IVP.java:87)
at com.objectdb.o.ISP.size(ISP.java:152)
at com.objectdb.o.CLT.visitRefs(CLT.java:156)
at com.objectdb.o.TVS.j(TVS.java:169)
at com.objectdb.o.TVS.cascade(TVS.java:156)
at com.objectdb.o.STA.Q(STA.java:476)
at com.objectdb.o.STM.D(STM.java:390)
at com.objectdb.o.OBM.bJ(OBM.java:884)
at com.objectdb.jdo.PMImpl.bJ(PMImpl.java:2186)
at com.objectdb.o.OBM.bI(OBM.java:800)
at com.objectdb.o.OBM.bH(OBM.java:750)
at com.objectdb.o.QRR.b(QRR.java:137)
at com.objectdb.o.QRR.b(QRR.java:634)
at com.objectdb.o.UMR.u(UMR.java:501)
at com.objectdb.o.ENT.loadInverse(ENT.java:1284)
at com.objectdb.o.IVP.h(IVP.java:100)
at com.objectdb.o.IVP.g(IVP.java:87)
at com.objectdb.o.IMP.values(IMP.java:153)
at java.util.Collections$UnmodifiableMap.values(Collections.java:1315)
at com.aqera.domains.one.activities.Aqera.z_getRegister(Aqera.java:152)
at com.aqera.domains.one.activities.Aqera.getRegister(Aqera.java:169)
at com.aqera.domains.one.simulator.datatypes.peopleandorgs.PersonActivity.z_registerPerson(PersonActivity.java:255)
at com.aqera.domains.one.simulator.datatypes.peopleandorgs.PersonActivity.registerPerson(PersonActivity.java:320)
at com.aqera.domains.one.simulator.datatypes.peopleandorgs.PeopleAndOrgData.z_load(PeopleAndOrgData.java:396)
at com.aqera.domains.one.simulator.datatypes.peopleandorgs.PeopleAndOrgData.load(PeopleAndOrgData.java:476)
at com.aqera.domains.one.simulator.SimulationWorkbook.z_go(SimulationWorkbook.java:286)
at com.aqera.domains.one.simulator.SimulationWorkbook.go(SimulationWorkbook.java:305)
at com.aqera.domains.one.scheduling.ScheduledActivity.z_run(ScheduledActivity.java:507)
at com.aqera.domains.one.scheduling.ScheduledActivity.run(ScheduledActivity.java:547)
at com.aqera.domains.one.scheduling.ScheduleActivityRun.z_run(ScheduleActivityRun.java:260)
at com.aqera.domains.one.scheduling.ScheduleActivityRun.run(ScheduleActivityRun.java:267)
at com.aqera.domains.one.scheduling.ScheduledActivityControl.z_runNextDay(ScheduledActivityControl.java:361)
at com.aqera.domains.one.scheduling.ScheduledActivityControl.runNextDay(ScheduledActivityControl.java:374)
at com.aqera.domains.one.simulator.SimulationSingleton.z_moveUpToActual(SimulationSingleton.java:1952)
at com.aqera.domains.one.simulator.SimulationSingleton.moveUpToActual(SimulationSingleton.java:1963)
at com.aqera.domains.one.simulator.SimulationTxnController.execute_MoveUpToActual(SimulationTxnController.java:307)
at com.aqera.domains.one.simulator.SimulationTxnController.execute_D1(SimulationTxnController.java:340)
at com.aqera.domains.one.simulator.SimulationTxnController.execute_M2(SimulationTxnController.java:285)
at com.aqera.domains.one.simulator.SimulationTxnController.end_Waiting(SimulationTxnController.java:359)
at com.aqera.domains.one.simulator.SimulationTxnController.receiveEvent_Run(SimulationTxnController.java:225)
at com.aqera.domains.one.simulator.SimulationTxnController.generateCallEvent(SimulationTxnController.java:206)
at com.aqera.domains.one.simulator.SimulationTxnController.moveUpTo(SimulationTxnController.java:149)
at com.aqera.domains.one.simulator.SimulationSingleton.z_moveUpTo(SimulationSingleton.java:787)
at com.aqera.domains.one.simulator.SimulationSingleton.moveUpTo(SimulationSingleton.java:795)
at com.aqera.domains.one.tests.SimulatorTest.testScheduleWorkbook(SimulatorTest.java:101)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at junit.framework.TestCase.runTest(TestCase.java:164)
at junit.framework.TestCase.runBare(TestCase.java:130)
at com.aqera.domains.one.tests.SimulatorTest.runBare(SimulatorTest.java:34)
at junit.framework.TestResult$1.protect(TestResult.java:106)
at junit.framework.TestResult.runProtected(TestResult.java:124)
at junit.framework.TestResult.run(TestResult.java:109)
at junit.framework.TestCase.run(TestCase.java:120)
at junit.framework.TestSuite.runTest(TestSuite.java:230)
at junit.framework.TestSuite.run(TestSuite.java:225)
at junit.framework.TestSuite.runTest(TestSuite.java:230)
at junit.framework.TestSuite.run(TestSuite.java:225)
at com.aqera.domains.one.tests.SimulatorTestSuite$1.run(SimulatorTestSuite.java:60)
at org.eclipse.jdt.internal.junit.runner.junit3.JUnit3TestReference.run(JUnit3TestReference.java:130)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

As before a Map structure was being accessed.

@OneToMany(cascade=CascadeType.ALL, mappedBy="z_aqera")
@MapKey(name="z_registerId")
    private java.util.Map<java.lang.String, com.aqera.domains.one.activities.AqeraRegister> z_registers  = new java.util.HashMap<java.lang.String, com.aqera.domains.one.activities.AqeraRegister>();

As before Enhancer is being run on code before test runs.

Thanks again.

The Maven project that causes this exception could help.

Sorry for the delay. We are seeing if we can make the thing any smaller.

We have spent some time tracking this down.

If we do not do static enhancing we do not get this bug.

The uploaded zip contains a maven project (  its also an Eclipse project ) which you can use to replicate the bug. We chose to use maven because of the static weaving step.

Thank you for the test case. Build 2.2.3_05 should fix the problem.