Maven Surefire并发修改异常

Question

当Maven构建我的项目并运行单元测试时，有时会抛出一个并发修改异常（大约5次中有1次会失败，其他时间会成功构建）。但是当我以单元测试的形式在本地运行测试时，它们都会毫无例外地通过。

在我的pom.xml文件我有Surefire插件配置为：

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-surefire-plugin</artifactId>
    <version>2.19.1</version>
    <configuration>
        <forkCount>1C</forkCount>
        <reuseForks>true</reuseForks>
    </configuration>
    <dependencies>
        <dependency>
              <groupId>org.apache.maven.surefire</groupId>
              <artifactId>surefire-junit47</artifactId>
              <version>2.19.1</version>
        </dependency>
    </dependencies>
</plugin>

然而，我得到的stackTrace没有提到是什么导致了并发修改异常。

我注意到所有的测试都通过了构建，但是出于某种原因，Maven重新打印了已经通过但现在有测试异常ConcurrentModification的测试结果。

我不确定是什么原因导致测试结果被重新打印，或者是否由于某种原因，测试在第一次测试没有完成的同时被重新运行，因为它是并行构建？（不知道为什么它会重新运行测试）

堆栈跟踪

[Test executing]

13:48:24.869 [00001-main] DEBUG o.s.t.c.s.DirtiesContextTestExecutionListener - After test method: context [DefaultTestContext@375046d6 testClass = Tests, testInstance = com.application.Tests@179181c, testMethod = failingTest@Tests, testException = [null], mergedContextConfiguration = [WebMergedContextConfiguration@3f7b4a61 testClass = Tests, locations = '{}', classes = '{class com.Application}', contextInitializerClasses = '[]', activeProfiles = '{}', propertySourceLocations = '{}', propertySourceProperties = '{}', resourceBasePath = 'src/main/app', contextLoader = 'org.springframework.test.context.web.WebDelegatingSmartContextLoader', parent = [null]]], class dirties context [false], class mode [null], method dirties context [false].
13:48:24.869 [00001-main] DEBUG o.s.t.c.w.ServletTestExecutionListener - Resetting RequestContextHolder for test context [DefaultTestContext@375046d6 testClass = Tests, testInstance = com.application.Tests@179181c, testMethod = failingTest@Tests, testException = [null], mergedContextConfiguration = [WebMergedContextConfiguration@3f7b4a61 testClass = Test, locations = '{}', classes = '{class com.Application}', contextInitializerClasses = '[]', activeProfiles = '{}', propertySourceLocations = '{}', propertySourceProperties = '{}', resourceBasePath = 'src/main/app', contextLoader = 'org.springframework.test.context.web.WebDelegatingSmartContextLoader', parent = [null]]].

[Some other tests executing]

13:48:28.632 [00001-main] DEBUG o.s.t.c.s.DirtiesContextTestExecutionListener - After test method: context [DefaultTestContext@54fde1bc testClass = Tests, testInstance = com.application.Tests@57ffa818, testMethod = failingTest@Tests, testException = java.util.ConcurrentModificationException, mergedContextConfiguration = [WebMergedContextConfiguration@5247834f testClass = Tests, locations = '{}', classes = '{class com.Application}', contextInitializerClasses = '[]', activeProfiles = '{}', propertySourceLocations = '{}', propertySourceProperties = '{}', resourceBasePath = 'src/main/app', contextLoader = 'org.springframework.test.context.web.WebDelegatingSmartContextLoader', parent = [null]]], class dirties context [false], class mode [null], method dirties context [false].
13:48:28.632 [00001-main] DEBUG o.s.t.c.w.ServletTestExecutionListener - Resetting RequestContextHolder for test context [DefaultTestContext@54fde1bc testClass = Tests, testInstance = com.application.Tests@57ffa818, testMethod = failingTest@Tests, testException = java.util.ConcurrentModificationException, mergedContextConfiguration = [WebMergedContextConfiguration@5247834f testClass = Tests, locations = '{}', classes = '{class com.Application}', contextInitializerClasses = '[]', activeProfiles = '{}', propertySourceLocations = '{}', propertySourceProperties = '{}', resourceBasePath = 'src/main/app', contextLoader = 'org.springframework.test.context.web.WebDelegatingSmartContextLoader', parent = [null]]].
failingTest(com.application.Tests)  Time elapsed: 0 sec  <<< ERROR!
java.util.ConcurrentModificationException

[Some other tests executing]

Results :

Tests in error: 
  Tests.failingTest» ConcurrentModification

我不确定是什么导致了并发修改异常，也不确定如何避免这个问题的发生，因为它只是偶尔发生，但失败的是同一个测试，而不是我的测试套件中的其他测试。

Answer 1

我也有同样的问题，但它与对集合所做的更改有关。Java8中的sort（）。更多信息。

Answer 2

我发现问题的出现是因为我没有模拟出一个创建和运行线程的方法（即使线程没有修改任何资源），所以我模拟了它，问题似乎得到了解决。