Question

经过this讨论之后，我被认为是附加到同一VM的选项，默认情况下已在OpenJDK11中禁用。

我正在尝试将Java代理升级到OpenJDK11，在调用VirtualMachine.attach(pid)的测试案例期间，我看到它失败并显示以下错误。处理这种情况的正确方法是什么？

完整的堆栈跟踪：

java.io.IOException: Can not attach to current VM

at jdk.attach/sun.tools.attach.HotSpotVirtualMachine.<init>(HotSpotVirtualMachine.java:75)
at jdk.attach/sun.tools.attach.VirtualMachineImpl.<init>(VirtualMachineImpl.java:48)
at jdk.attach/sun.tools.attach.AttachProviderImpl.attachVirtualMachine(AttachProviderImpl.java:69)
at jdk.attach/com.sun.tools.attach.VirtualMachine.attach(VirtualMachine.java:207)
at org.kantega.notsoserial.WithAgentIT.attachAgent(WithAgentIT.java:76)
at org.kantega.notsoserial.WithAgentIT.attackShouldBePreventedWithAgent(WithAgentIT.java:47)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)

Answer 1

我不确定这是否对每个人都有帮助，但就我而言，这是一个测试用例，用于测试代理是否正确连接到JDK（当代理实际连接到JDK时，它不会是自连接的） JDK，即实际运行时不是测试用例。

根据@Holger的建议，在评论中，我修改了maven-failsafe-plugin以允许自我附加。

        <plugin>
            <artifactId>maven-failsafe-plugin</artifactId>
            <version>2.22.2</version>
            <executions>
                <execution>
                    <goals>
                        <goal>integration-test</goal>
                        <goal>verify</goal>
                    </goals>
                    <configuration>
                        <argLine>-Djdk.attach.allowAttachSelf=true</argLine>
                        <forkMode>once</forkMode>
                    </configuration>
                </execution>
            </executions>
        </plugin>

Answer 2

请参见JDK-8180425 : Release Note: Attach API cannot be used to attach to the current VM by default：

在JDK 9中，附加API的实现已更改，默认情况下不允许附加到当前VM。此更改对使用Attach API附加到正在运行的VM的工具没有影响。这可能会影响滥用此API作为获取java.lang.instrument API的一种方式的库。可以在命令行上设置系统属性jdk.attach.allowAttachSelf，以减轻对此更改的任何兼容性。

Answer 3

这通过在maven-surefire-plugin中添加javaagent为我工作

<plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-surefire-plugin</artifactId>
        <version>${maven-surefire-plugin.version}</version>
        <configuration>
          <!-- Centralize test reports in parent project -->
          <reportsDirectory>${basedir}/../target/surefire-reports</reportsDirectory>
          <!-- Sets the VM argument line used for Jacoco when unit tests are run. -->
          <argLine>
             -javaagent:${settings.localRepository}/org/jmockit/jmockit/${jmockit.version}/jmockit-${jmockit.version}.jar ${surefireArgLine}
          </argLine>
        </configuration> 
</plugin>

VirtualMachine.attach（pid）失败，并出现java.io.IOException：无法连接到当前VM

3 个答案: