ExecutorBeanPostProcessor Makes Guava's ListeningExecutorService Beans Unusable

[jwcarman]

We recently upgraded to Spring Boot 2.1.0 (with spring-cloud-sleuth-core 2.0.2.RELEASE) and for our apps that use a Guava ListeningExecutorService, exposed as a bean, they have started getting the following exception:

org.springframework.beans.factory.BeanNotOfRequiredTypeException: Bean named 'batchExecutorService' is expected to be of type 'com.google.common.util.concurrent.ListeningExecutorService' but was actually of type 'org.springframework.cloud.sleuth.instrument.async.TraceableExecutorService'

[marcingrzejszczak]

Can you create a sample that replicates this problem?

[jwcarman]

You want it attached or just upload it to GH in my account?

[marcingrzejszczak]

Gh account is good

[jwcarman]

Okay, I finally figured it out. Since we don't have a Greenwich release in central, we're still using Finchley.SR2. Since that's likely a no-no with Spring Boot 2.1.x, I downgraded Spring Boot to 2.0.6.RELEASE. The key appears to be the devtools, though (which would be gone at runtime normally). If you try to start this project from within your IDE (I use IDEA), it will fail. If you comment out the devtools dependency, it'll run.

https://github.com/jwcarman/spring-cloud-sleuth-guava

Hope this helps. Thanks, @marcingrzejszczak !

[marcingrzejszczak]

The exception is related to

org.springframework.aop.framework.AopConfigException: Could not generate CGLIB subclass of class com.google.common.util.concurrent.MoreExecutors$ListeningDecorator: Common causes of this problem include using a final class or a non-visible class; nested exception is org.springframework.cglib.core.CodeGenerationException: java.lang.reflect.InvocationTargetException-->null

the concrete reason for that (coming from the LoadingCache from Spring's CGLIB module) is

class com.google.common.util.concurrent.MoreExecutors$ListeningDecorator$$EnhancerBySpringCGLIB$$152e166c cannot access its superclass com.google.common.util.concurrent.MoreExecutors$ListeningDecorator

that's due to the fact that ListeningDecorator is a private static one, and we can't instrument it. I have no idea why it works in the first place ;)

please help :D @aclement @philwebb

[marcingrzejszczak]

Is this still a problem? I can't replicate this when running the sample locally with latest versions (maybe I'm doing sth wrong)

[jwcarman]

Oh my gosh, I totally forgot to provide a sample to you all. So sorry. This has been a while, but let me see what I can whip up. It may have very well already been addressed.