由於 javax.validation 異常導致的 ConcurrentModification 異常

Question

我正面臨這個奇怪的問題，api 由於 javax.validation 問題而引發並發修改異常。

    java.util.ConcurrentModificationException: null
    at java.util.HashMap$HashIterator.nextNode(HashMap.java:1445) ~[na:1.8.0_265]
    at java.util.HashMap$ValueIterator.next(HashMap.java:1474) ~[na:1.8.0_265]
    at org.eclipse.persistence.jpa.PersistenceProvider.isLoadedWithReference(PersistenceProvider.java:464) ~[eclipselink-2.6.1.jar:2.6.1.v20150916-55dc7c3]
    at javax.persistence.Persistence$PersistenceUtilImpl.isLoaded(Persistence.java:154) ~[javax.persistence-2.1.0.jar:2.1.0]
    at org.hibernate.validator.internal.engine.resolver.JPATraversableResolver.isReachable(JPATraversableResolver.java:56) ~[bean-validator-2.2.0.jar:5.0.0.Final]
    at org.hibernate.validator.internal.engine.resolver.DefaultTraversableResolver.isReachable(DefaultTraversableResolver.java:130) ~[bean-validator-2.2.0.jar:5.0.0.Final]
    at org.hibernate.validator.internal.engine.resolver.SingleThreadCachedTraversableResolver.isReachable(SingleThreadCachedTraversableResolver.java:46) ~[bean-validator-2.2.0.jar:5.0.0.Final] [1 skipped]
    at org.hibernate.validator.internal.engine.ValidatorImpl.isReachable(ValidatorImpl.java:1307) ~[bean-validator-2.2.0.jar:5.0.0.Final]
    at org.hibernate.validator.internal.engine.ValidatorImpl.isValidationRequired(ValidatorImpl.java:1292) ~[bean-validator-2.2.0.jar:5.0.0.Final]
    ... 49 common frames omitted
Wrapped by: javax.validation.ValidationException: HV000041: Call to TraversableResolver.isReachable() threw an exception.
    at org.hibernate.validator.internal.engine.ValidatorImpl.isReachable(ValidatorImpl.java:1316) ~[bean-validator-2.2.0.jar:5.0.0.Final]
    at org.hibernate.validator.internal.engine.ValidatorImpl.isValidationRequired(ValidatorImpl.java:1292) ~[bean-validator-2.2.0.jar:5.0.0.Final]
    at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraint(ValidatorImpl.java:475) ~[bean-validator-2.2.0.jar:5.0.0.Final]
    at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForDefaultGroup(ValidatorImpl.java:424) ~[bean-validator-2.2.0.jar:5.0.0.Final]
    at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForCurrentGroup(ValidatorImpl.java:388) ~[bean-validator-2.2.0.jar:5.0.0.Final]
    at org.hibernate.validator.internal.engine.ValidatorImpl.validateInContext(ValidatorImpl.java:340) ~[bean-validator-2.2.0.jar:5.0.0.Final]
    at org.hibernate.validator.internal.engine.ValidatorImpl.validateCascadedConstraint(ValidatorImpl.java:635) ~[bean-validator-2.2.0.jar:5.0.0.Final]
    at org.hibernate.validator.internal.engine.ValidatorImpl.validateCascadedConstraints(ValidatorImpl.java:524) ~[bean-validator-2.2.0.jar:5.0.0.Final]
    at org.hibernate.validator.internal.engine.ValidatorImpl.validateInContext(ValidatorImpl.java:349) ~[bean-validator-2.2.0.jar:5.0.0.Final]
    at org.hibernate.validator.internal.engine.ValidatorImpl.validateCascadedConstraint(ValidatorImpl.java:635) ~[bean-validator-2.2.0.jar:5.0.0.Final]
    at org.hibernate.validator.internal.engine.ValidatorImpl.validateCascadedConstraints(ValidatorImpl.java:524) ~[bean-validator-2.2.0.jar:5.0.0.Final]
    at org.hibernate.validator.internal.engine.ValidatorImpl.validateParametersInContext(ValidatorImpl.java:916) ~[bean-validator-2.2.0.jar:5.0.0.Final]
    at org.hibernate.validator.internal.engine.ValidatorImpl.validateParameters(ValidatorImpl.java:240) ~[bean-validator-2.2.0.jar:5.0.0.Final]
    at org.hibernate.validator.internal.engine.ValidatorImpl.validateParameters(ValidatorImpl.java:198) ~[bean-validator-2.2.0.jar:5.0.0.Final]
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1095) [webapp-runner.jar:na] [28 skipped]
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:672) [webapp-runner.jar:na]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1502) [webapp-runner.jar:na]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1458) [webapp-runner.jar:na]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_265]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_265]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [webapp-runner.jar:na]
    at java.lang.Thread.run(Thread.java:748) [na:1.8.0_265]

堆棧跟蹤沒有說明 bean 中的哪個驗證導致了問題。

Answer 1

看起來堆棧跟蹤正在以一種特殊的方式被...格式化。

顯示它的正常方式是首先顯示主要異常，然后是cause （或包裝的）異常鏈。 但是您向我們展示的內容是包裝的異常，然后是包裝它的異常。

所以這意味着ConcurrentModificationException導致了ValidationException ...而不是相反。

不幸的是，這並不能解釋實際發生了什么。

Answer 2

顯然，異常堆棧跟蹤表明 hashmap 中發生了並發修改異常。 Concurrent modification exception can happen if you use Iterators while traversing map values or API which are not thread safe like the Generic Hashmap object. 嘗試使用並發 hashmap 並且您的問題應該得到解決。