@bsideup can you have a look ? It works with all other JDK version that we use on the CI :/ @normanmaurer JDK13+ requires a flag ( `-XX:+AllowRedefinitionToAddDeleteMethod` ) to be set, see https://github.com/reactor/BlockHound/issues/33 for more details.

We're still investigating what to do about it, since it was a behaviour change in OpenJDK's instrumentation logic... @bsideup I see... I will add these to the java13 profile then for now. @bsideup this did not work :(

```
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-surefire-plugin:2.22.1:test (default-test) on project netty-transport-blockhound-tests: There are test failures.
[ERROR]
[ERROR] Please refer to /Users/norman/Documents/workspace/netty/transport-blockhound-tests/target/surefire-reports for the individual test results.
[ERROR] Please refer to dump files (if any exist) [date].dump, [date]-jvmRun[N].dump and [date].dumpstream.
[ERROR] The forked VM terminated without properly saying goodbye. VM crash or System.exit called?
[ERROR] Command was /bin/sh -c cd /Users/norman/Documents/workspace/netty/transport-blockhound-tests && /Users/norman/.jabba/jdk/adopt@1.13.0-1/Contents/Home/bin/java -server -dsa -da -ea:io.netty... -XX:+HeapDumpOnOutOfMemoryError -XX:+PrintGCDetails -XX:+AllowRedefinitionToAddDeleteMethod -D_ -D_ -D_ -D_ -jar /Users/norman/Documents/workspace/netty/transport-blockhound-tests/target/surefire/surefirebooter16207235744509438163.jar /Users/norman/Documents/workspace/netty/transport-blockhound-tests/target/surefire 2019-10-31T11-59-30_222-jvmRun1 surefire15970040776949416610tmp surefire_08978095701992529987tmp
[ERROR] Error occurred in starting fork, check output in log
[ERROR] Process Exit Code: 1
[ERROR] org.apache.maven.surefire.booter.SurefireBooterForkException: The forked VM terminated without properly saying goodbye. VM crash or System.exit called?
[ERROR] Command was /bin/sh -c cd /Users/norman/Documents/workspace/netty/transport-blockhound-tests && /Users/norman/.jabba/jdk/adopt@1.13.0-1/Contents/Home/bin/java -server -dsa -da -ea:io.netty... -XX:+HeapDumpOnOutOfMemoryError -XX:+PrintGCDetails -XX:+AllowRedefinitionToAddDeleteMethod -D_ -D_ -D_ -D_ -jar /Users/norman/Documents/workspace/netty/transport-blockhound-tests/target/surefire/surefirebooter16207235744509438163.jar /Users/norman/Documents/workspace/netty/transport-blockhound-tests/target/surefire 2019-10-31T11-59-30_222-jvmRun1 surefire15970040776949416610tmp surefire_08978095701992529987tmp
[ERROR] Error occurred in starting fork, check output in log
[ERROR] Process Exit Code: 1
[ERROR] 	at org.apache.maven.plugin.surefire.booterclient.ForkStarter.fork(ForkStarter.java:669)
[ERROR] 	at org.apache.maven.plugin.surefire.booterclient.ForkStarter.run(ForkStarter.java:282)
[ERROR] 	at org.apache.maven.plugin.surefire.booterclient.ForkStarter.run(ForkStarter.java:245)
[ERROR] 	at org.apache.maven.plugin.surefire.AbstractSurefireMojo.executeProvider(AbstractSurefireMojo.java:1183)
[ERROR] 	at org.apache.maven.plugin.surefire.AbstractSurefireMojo.executeAfterPreconditionsChecked(AbstractSurefireMojo.java:1011)
[ERROR] 	at org.apache.maven.plugin.surefire.AbstractSurefireMojo.execute(AbstractSurefireMojo.java:857)
[ERROR] 	at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:134)
[ERROR] 	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:208)
[ERROR] 	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:154)
[ERROR] 	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:146)
[ERROR] 	at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:117)
[ERROR] 	at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:81)
[ERROR] 	at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51)
[ERROR] 	at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:128)
[ERROR] 	at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:309)
[ERROR] 	at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:194)
[ERROR] 	at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:107)
[ERROR] 	at org.apache.maven.cli.MavenCli.execute(MavenCli.java:955)
[ERROR] 	at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:290)
[ERROR] 	at org.apache.maven.cli.MavenCli.main(MavenCli.java:194)
[ERROR] 	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[ERROR] 	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
[ERROR] 	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
[ERROR] 	at java.base/java.lang.reflect.Method.invoke(Method.java:567)
[ERROR] 	at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289)
[ERROR] 	at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)
[ERROR] 	at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)
[ERROR] 	at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)
[ERROR] 	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[ERROR] 	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
[ERROR] 	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
[ERROR] 	at java.base/java.lang.reflect.Method.invoke(Method.java:567)
[ERROR] 	at org.apache.maven.wrapper.BootstrapMainStarter.start(BootstrapMainStarter.java:39)
[ERROR] 	at org.apache.maven.wrapper.WrapperExecutor.execute(WrapperExecutor.java:122)
[ERROR] 	at org.apache.maven.wrapper.MavenWrapperMain.main(MavenWrapperMain.java:60)
[ERROR]
[ERROR] -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException
``` @normanmaurer on it, trying locally @bsideup thanks... PRs welcome :) @normanmaurer interesting. It works when I run BlockHound's tests with Java 13 but fails in Netty.
I will continue the investigation and eventually send a PR.

Trying to find how to check that the flag is actually set in the tests' JVM... status update:
I am still unable to fix it in Netty, although it seems to work in isolation:
https://gist.github.com/bsideup/02d09c5723d956b27c958fa881de5495

Checking whether it is a problem with BlockHound or with the whitelisting we do in the integration, so that the call is instrumented but not reported

**update 2:**
running it from IntelliJ with JDK13 + `-XX:+AllowRedefinitionToAddDeleteMethods` works. Seems to be something related to Maven... Ok, it seems that Maven was using an old SNAPSHOT from pre-BlockHound era, this is why running it with IDEA was giving me a positive result but with Maven I was getting errors.

I submitted #9742 with a simple profile-based fix, and will submit another one with a test checking that `ServiceLoader` can load the integration Ok, I think now we're good :) #9743 is an optional addition to make it easier to debug issues in future, since I spent quite some time fighting with JDK13 while the problem was in my Maven setup and Maven's vision on how modular projects should be built 😅
NettyBlockHoundIntegrationTest.testBlockingCallsInNettyThreads fails with JDK 13
```
[INFO] --- xml-maven-plugin:1.0.1:check-format (check-style) @ netty-transport-blockhound-tests ---
[INFO] 
[INFO] --- maven-dependency-plugin:2.10:get (get-jetty-alpn-agent) @ netty-transport-blockhound-tests ---
[INFO] Resolving org.mortbay.jetty.alpn:jetty-alpn-agent:jar:2.0.8 with transitive dependencies
[INFO] 
[INFO] --- build-helper-maven-plugin:1.10:parse-version (parse-version) @ netty-transport-blockhound-tests ---
[INFO] 
[INFO] --- maven-antrun-plugin:1.8:run (write-version-properties) @ netty-transport-blockhound-tests ---
[INFO] Executing tasks

main:
     [echo] Current commit: 47f82b6 on 2019-10-30 19:36:03 +0100
    [mkdir] Created dir: /code/transport-blockhound-tests/target/classes/META-INF
[propertyfile] Creating new property file: /code/transport-blockhound-tests/target/classes/META-INF/io.netty.versions.properties
[INFO] Executed tasks
[INFO] 
[INFO] --- maven-remote-resources-plugin:1.5:process (default) @ netty-transport-blockhound-tests ---
[INFO] 
[INFO] --- maven-resources-plugin:3.0.1:resources (default-resources) @ netty-transport-blockhound-tests ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] skip non existing resourceDirectory /code/transport-blockhound-tests/src/main/resources
[INFO] 
[INFO] --- maven-compiler-plugin:3.8.0:compile (default-compile) @ netty-transport-blockhound-tests ---
[INFO] No sources to compile
[INFO] 
[INFO] --- forbiddenapis:2.2:check (check-forbidden-apis) @ netty-transport-blockhound-tests ---
[INFO] Skipping forbidden-apis checks.
[INFO] 
[INFO] --- animal-sniffer-maven-plugin:1.16:check (default) @ netty-transport-blockhound-tests ---
[INFO] Checking unresolved references to org.codehaus.mojo.signature:java18:1.0
[INFO] 
[INFO] >>> maven-bundle-plugin:2.5.4:manifest (generate-manifest) > process-classes @ netty-transport-blockhound-tests >>>
[INFO] 
[INFO] --- maven-enforcer-plugin:3.0.0-M1:enforce (enforce-maven) @ netty-transport-blockhound-tests ---
[INFO] 
[INFO] --- maven-enforcer-plugin:3.0.0-M1:enforce (enforce-tools) @ netty-transport-blockhound-tests ---
[INFO] 
[INFO] --- maven-checkstyle-plugin:3.0.0:check (check-style) @ netty-transport-blockhound-tests ---
[INFO] Starting audit...
Audit done.
[INFO] 
[INFO] --- xml-maven-plugin:1.0.1:check-format (check-style) @ netty-transport-blockhound-tests ---
[INFO] 
[INFO] --- maven-dependency-plugin:2.10:get (get-jetty-alpn-agent) @ netty-transport-blockhound-tests ---
[INFO] Resolving org.mortbay.jetty.alpn:jetty-alpn-agent:jar:2.0.8 with transitive dependencies
[INFO] 
[INFO] --- build-helper-maven-plugin:1.10:parse-version (parse-version) @ netty-transport-blockhound-tests ---
[INFO] 
[INFO] --- maven-antrun-plugin:1.8:run (write-version-properties) @ netty-transport-blockhound-tests ---
[INFO] Executing tasks

main:
     [echo] Current commit: 47f82b6 on 2019-10-30 19:36:03 +0100
   [delete] Deleting: /code/transport-blockhound-tests/target/classes/META-INF/io.netty.versions.properties
[propertyfile] Creating new property file: /code/transport-blockhound-tests/target/classes/META-INF/io.netty.versions.properties
[INFO] Executed tasks
[INFO] 
[INFO] --- maven-remote-resources-plugin:1.5:process (default) @ netty-transport-blockhound-tests ---
[INFO] 
[INFO] --- maven-resources-plugin:3.0.1:resources (default-resources) @ netty-transport-blockhound-tests ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] skip non existing resourceDirectory /code/transport-blockhound-tests/src/main/resources
[INFO] 
[INFO] --- maven-compiler-plugin:3.8.0:compile (default-compile) @ netty-transport-blockhound-tests ---
[INFO] No sources to compile
[INFO] 
[INFO] --- forbiddenapis:2.2:check (check-forbidden-apis) @ netty-transport-blockhound-tests ---
[INFO] Skipping forbidden-apis checks.
[INFO] 
[INFO] --- animal-sniffer-maven-plugin:1.16:check (default) @ netty-transport-blockhound-tests ---
[INFO] Checking unresolved references to org.codehaus.mojo.signature:java18:1.0
[INFO] 
[INFO] <<< maven-bundle-plugin:2.5.4:manifest (generate-manifest) < process-classes @ netty-transport-blockhound-tests <<<
[INFO] 
[INFO] 
[INFO] --- maven-bundle-plugin:2.5.4:manifest (generate-manifest) @ netty-transport-blockhound-tests ---
[WARNING] Manifest io.netty:netty-transport-blockhound-tests:jar:5.0.0.Final-SNAPSHOT : Unused Export-Package instructions: [io.netty.*] 
[WARNING] Manifest io.netty:netty-transport-blockhound-tests:jar:5.0.0.Final-SNAPSHOT : Unused Import-Package instructions: [sun.misc.*, sun.security.*] 
[INFO] 
[INFO] --- maven-resources-plugin:3.0.1:testResources (default-testResources) @ netty-transport-blockhound-tests ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] skip non existing resourceDirectory /code/transport-blockhound-tests/src/test/resources
[INFO] 
[INFO] --- maven-compiler-plugin:3.8.0:testCompile (default-testCompile) @ netty-transport-blockhound-tests ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 1 source file to /code/transport-blockhound-tests/target/test-classes
[INFO] 
[INFO] --- forbiddenapis:2.2:testCheck (check-forbidden-test-apis) @ netty-transport-blockhound-tests ---
[INFO] Skipping forbidden-apis checks.
[INFO] 
[INFO] --- maven-surefire-plugin:2.22.1:test (default-test) @ netty-transport-blockhound-tests ---
[INFO] 
[INFO] -------------------------------------------------------
[INFO]  T E S T S
[INFO] -------------------------------------------------------
[WARNING] Corrupted STDOUT by directly writing to native stream in forked JVM 1. See FAQ web page and the dump file /code/transport-blockhound-tests/target/surefire-reports/2019-10-31T01-09-13_174-jvmRun1.dumpstream
[INFO] Running io.netty.util.internal.NettyBlockHoundIntegrationTest
01:33:52.851 [main] DEBUG i.n.u.i.l.InternalLoggerFactory - Using SLF4J as the default logging framework
01:33:52.866 [main] DEBUG i.n.u.i.InternalThreadLocalMap - -Dio.netty.threadLocalMap.stringBuilder.initialSize: 1024
01:33:52.866 [main] DEBUG i.n.u.i.InternalThreadLocalMap - -Dio.netty.threadLocalMap.stringBuilder.maxSize: 4096
[ERROR] Tests run: 1, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 1.521 s <<< FAILURE! - in io.netty.util.internal.NettyBlockHoundIntegrationTest
[ERROR] testBlockingCallsInNettyThreads(io.netty.util.internal.NettyBlockHoundIntegrationTest)  Time elapsed: 0.32 s  <<< FAILURE!
java.lang.AssertionError: Expected an exception due to a blocking call but none was thrown
	at org.junit.Assert.fail(Assert.java:88)
	at io.netty.util.internal.NettyBlockHoundIntegrationTest.testBlockingCallsInNettyThreads(NettyBlockHoundIntegrationTest.java:48)
	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:567)
	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.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:365)
	at org.apache.maven.surefire.junit4.JUnit4Provider.executeWithRerun(JUnit4Provider.java:273)
	at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:238)
	at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:159)
	at org.apache.maven.surefire.booter.ForkedBooter.invokeProviderInSameClassLoader(ForkedBooter.java:384)
	at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:345)
	at org.apache.maven.surefire.booter.ForkedBooter.execute(ForkedBooter.java:126)
	at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:418)

[INFO] 
[INFO] Results:
[INFO] 
[ERROR] Failures: 
[ERROR]   NettyBlockHoundIntegrationTest.testBlockingCallsInNettyThreads:48 Expected an exception due to a blocking call but none was thrown
[INFO] 
[ERROR] Tests run: 1, Failures: 1, Errors: 0, Skipped: 0
[INFO] 
```
transport-blockhound-tests/pom.xml
transport-blockhound-tests/pom.xml
diff --git a/transport-blockhound-tests/pom.xml b/transport-blockhound-tests/pom.xml
index 9105858435e..c0a0c8d3ddd 100644
--- a/transport-blockhound-tests/pom.xml
+++ b/transport-blockhound-tests/pom.xml
@@ -31,6 +31,18 @@
 
   <name>Netty/Transport/BlockHound/Tests</name>
 
+  <profiles>
+    <profile>
+      <id>java13</id>
+      <activation>
+        <jdk>13</jdk>
+      </activation>
+      <properties>
+        <argLine.common>-XX:+AllowRedefinitionToAddDeleteMethods</argLine.common>
+      </properties>
+    </profile>
+  </profiles>
+
   <properties>
     <maven.compiler.source>1.8</maven.compiler.source>
     <maven.compiler.target>1.8</maven.compiler.target>
