Jpa persist / merge在循环内抛出ConcurrentModificationException

时间：2014-08-26 12:25:08

标签： java jpa

假设我有一个存储属于该人的汽车的实体人员。

@Entity
@Table
public class Person imlpements Serializable
{
    @OneToMany(mappedBy = "person")
    private List<Car> cars = new ArrayList<Car>();
}

@Entity
@Table
public class Car imlpements Serializable
{
   @ManyToOne(cascade = CascadeType.ALL, fetch = FetchType.LAZY)
  @JoinColumn(name = "person_id")
    private Person person
}

我想坚持汽车。它抛出ConcurrentModificationException。我没理由

for (Car car : person.getCars())
{
   em.merge(car)
}

编辑。这是我的实体经理：

@PersistenceContext(unitName = "DBService")
private EntityManager em;

这是堆栈跟踪

at java.util.AbstractList$Itr.checkForComodification(AbstractList.java:372) [:1.6.0_30]
at java.util.AbstractList$Itr.next(AbstractList.java:343) [:1.6.0_30]
at org.hibernate.collection.AbstractPersistentCollection$IteratorProxy.next(AbstractPersistentCollection.java:580) [:3.6.0.Final]
at com.importer Import.findCars(Import.java:114) [:]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [:1.6.0_30]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) [:1.6.0_30]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) [:1.6.0_30]
at java.lang.reflect.Method.invoke(Method.java:597) [:1.6.0_30]
at org.jboss.aop.joinpoint.MethodInvocation.invokeTarget(MethodInvocation.java:122) [jboss-aop.jar:2.2.1.GA]
at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:111) [jboss-aop.jar:2.2.1.GA]
at org.jboss.ejb3.interceptors.container.ContainerMethodInvocationWrapper.invokeNext(ContainerMethodInvocationWrapper.java:72) [:1.1.3]
at org.jboss.ejb3.interceptors.aop.InterceptorSequencer.invoke(InterceptorSequencer.java:76) [:1.1.3]
at org.jboss.ejb3.interceptors.aop.InterceptorSequencer.aroundInvoke(InterceptorSequencer.java:62) [:1.1.3]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [:1.6.0_30]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) [:1.6.0_30]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) [:1.6.0_30]
at java.lang.reflect.Method.invoke(Method.java:597) [:1.6.0_30]
at org.jboss.aop.advice.PerJoinpointAdvice.invoke(PerJoinpointAdvice.java:174) [jboss-aop.jar:2.2.1.GA]
at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]
at org.jboss.ejb3.interceptors.aop.InvocationContextInterceptor.fillMethod(InvocationContextInterceptor.java:74) [:1.1.3]
at org.jboss.aop.advice.org.jboss.ejb3.interceptors.aop.InvocationContextInterceptor_z_fillMethod_10768571.invoke(InvocationContextInterceptor_z_fillMethod_10768571.java) [:]
at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]
at org.jboss.ejb3.interceptors.aop.InvocationContextInterceptor.setup(InvocationContextInterceptor.java:90) [:1.1.3]
at org.jboss.aop.advice.org.jboss.ejb3.interceptors.aop.InvocationContextInterceptor_z_setup_10768571.invoke(InvocationContextInterceptor_z_setup_10768571.java) [:]
at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]
at org.jboss.ejb3.async.impl.interceptor.AsynchronousServerInterceptor.invoke(AsynchronousServerInterceptor.java:128) [:1.7.17]
at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]
at org.jboss.ejb3.connectionmanager.CachedConnectionInterceptor.invoke(CachedConnectionInterceptor.java:62) [:1.7.17]
at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]
at org.jboss.ejb3.entity.TransactionScopedEntityManagerInterceptor.invoke(TransactionScopedEntityManagerInterceptor.java:56) [:1.7.17]
at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]
at org.jboss.ejb3.concurrency.aop.interceptor.ContainerManagedConcurrencyInterceptor.invoke(ContainerManagedConcurrencyInterceptor.java:181) [:1.0.0-alpha-4]
at org.jboss.aop.advice.PerInstanceInterceptor.invoke(PerInstanceInterceptor.java:86) [jboss-aop.jar:2.2.1.GA]
at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]
at org.jboss.ejb3.AllowedOperationsInterceptor.invoke(AllowedOperationsInterceptor.java:47) [:1.7.17]
at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]
at org.jboss.ejb3.tx.NullInterceptor.invoke(NullInterceptor.java:42) [:1.0.3]
at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]
at org.jboss.ejb3.core.context.SessionInvocationContextAdapter.proceed(SessionInvocationContextAdapter.java:95) [:1.7.17]
at org.jboss.ejb3.tx2.impl.CMTTxInterceptor.invokeInOurTx(CMTTxInterceptor.java:247) [:0.0.1]
at org.jboss.ejb3.tx2.impl.CMTTxInterceptor.required(CMTTxInterceptor.java:349) [:0.0.1]
at org.jboss.ejb3.tx2.impl.CMTTxInterceptor.invoke(CMTTxInterceptor.java:209) [:0.0.1]
at org.jboss.ejb3.tx2.aop.CMTTxInterceptorWrapper.invoke(CMTTxInterceptorWrapper.java:52) [:0.0.1]
at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]
at org.jboss.aspects.tx.TxPropagationInterceptor.invoke(TxPropagationInterceptor.java:76) [:1.0.0.GA]
at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]
at org.jboss.ejb3.tx.NullInterceptor.invoke(NullInterceptor.java:42) [:1.0.3]
at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]
at org.jboss.ejb3.async.impl.interceptor.AsynchronousClientInterceptor.invoke(AsynchronousClientInterceptor.java:143) [:1.7.17]
at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]
at org.jboss.ejb3.ENCPropagationInterceptor.invoke(ENCPropagationInterceptor.java:41) [:1.7.17]
at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]
at org.jboss.ejb3.BlockContainerShutdownInterceptor.invoke(BlockContainerShutdownInterceptor.java:67) [:1.7.17]
at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]
at org.jboss.ejb3.core.context.CurrentInvocationContextInterceptor.invoke(CurrentInvocationContextInterceptor.java:47) [:1.7.17]
at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]
at org.jboss.aspects.currentinvocation.CurrentInvocationInterceptor.invoke(CurrentInvocationInterceptor.java:67) [:1.0.1]
at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]
at org.jboss.ejb3.interceptor.EJB3TCCLInterceptor.invoke(EJB3TCCLInterceptor.java:86) [:1.7.17]
at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]
at org.jboss.ejb3.singleton.aop.impl.AOPBasedInterceptorRegistry.intercept(AOPBasedInterceptorRegistry.java:110) [:1.0.0-alpha-28]
at org.jboss.ejb3.singleton.impl.container.SingletonContainer.invoke(SingletonContainer.java:206) [:1.0.0-alpha-28]
at org.jboss.ejb3.singleton.aop.impl.AOPBasedSingletonContainer.dynamicInvoke(AOPBasedSingletonContainer.java:432) [:1.0.0-alpha-28]
at org.jboss.ejb3.session.InvokableContextClassProxyHack._dynamicInvoke(InvokableContextClassProxyHack.java:53) [:1.7.17]
at org.jboss.aop.Dispatcher.invoke(Dispatcher.java:91) [jboss-aop.jar:2.2.1.GA]
at org.jboss.aspects.remoting.AOPRemotingInvocationHandler.invoke(AOPRemotingInvocationHandler.java:82) [:1.0.1.GA]
at org.jboss.remoting.ServerInvoker.invoke(ServerInvoker.java:898) [:6.0.0.Final]
at org.jboss.remoting.transport.socket.ServerThread.completeInvocation(ServerThread.java:791) [:6.0.0.Final]
at org.jboss.remoting.transport.socket.ServerThread.processInvocation(ServerThread.java:744) [:6.0.0.Final]
at org.jboss.remoting.transport.socket.ServerThread.dorun(ServerThread.java:548) [:6.0.0.Final]
at org.jboss.remoting.transport.socket.ServerThread.run(ServerThread.java:234) [:6.0.0.Final]

1 个答案:

答案 0 :(得分：4)

在迭代该列表时，您似乎正在修改Person.cars列表。这是不允许的。

我怀疑发生的事情是：

  1. 您迭代Person.cars列表，并为每个项目...
  2. 您持久保存Car对象。
  3. 持久Car个对象导致Hibernate需要更新汽车所有者的Person.cars列表。该列表与您在步骤1中迭代的列表相同，因此您获得ConcurrentModificationException

    4. 您可以尝试使用以下方法的解决方案：

    CopyOnWriteArrayList<Car> personCars = 
    new CopyOnWriteArrayList<Car>( person.getCars() );

for (Car c : personCars) em.merge(c);

    此致

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