How to get rid of Unable to create annotation scanner for web module: null error while deploying war file on Tomee?

Question

Whenever I add Swagger dependencies to my REST API project and I try to deploy it on Apache Tomee as earlier (without those dependencies its works completly fine), it fails to start due to the following error:

19-Sep-2019 06:54:26.267 SEVERE [localhost-startStop-1] sun.reflect.NativeMethodAccessorImpl.invoke ContainerBase.addChild: start:
 org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/my-rest-api]]
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167)
        at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:752)
        at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:728)
        at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:734)
        at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:952)
        at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1823)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
        at java.lang.Thread.run(Thread.java:748)
Caused by: org.apache.tomee.catalina.TomEERuntimeException: org.apache.openejb.OpenEJBException: Unable to create annotation scanner for web module my-rest-api: null
        at org.apache.tomee.catalina.TomcatWebAppBuilder.loadApplication(TomcatWebAppBuilder.java:2299)
        at org.apache.tomee.catalina.TomcatWebAppBuilder.startInternal(TomcatWebAppBuilder.java:1187)
        at org.apache.tomee.catalina.TomcatWebAppBuilder.configureStart(TomcatWebAppBuilder.java:1124)
        at org.apache.tomee.catalina.GlobalListenerSupport.lifecycleEvent(GlobalListenerSupport.java:133)
        at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:94)
        at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5087)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
        ... 10 more
Caused by: org.apache.openejb.OpenEJBException: Unable to create annotation scanner for web module my-rest-api: null
        at org.apache.openejb.config.DeploymentLoader.addWebModule(DeploymentLoader.java:886)
        at org.apache.openejb.config.DeploymentLoader.load(DeploymentLoader.java:233)
        at org.apache.tomee.catalina.TomcatWebAppBuilder.loadApplication(TomcatWebAppBuilder.java:2297)
        ... 16 more
Caused by: java.lang.IllegalArgumentException
        at org.apache.xbean.asm5.ClassReader.<init>(Unknown Source)
        at org.apache.xbean.asm5.ClassReader.<init>(Unknown Source)
        at org.apache.xbean.asm5.ClassReader.<init>(Unknown Source)
        at org.apache.xbean.finder.AnnotationFinder.readClassDef(AnnotationFinder.java:1169)
        at org.apache.xbean.finder.AnnotationFinder.<init>(AnnotationFinder.java:147)
        at org.apache.xbean.finder.AnnotationFinder.<init>(AnnotationFinder.java:160)
        at org.apache.openejb.config.FinderFactory$OpenEJBAnnotationFinder.<init>(FinderFactory.java:546)
        at org.apache.openejb.config.FinderFactory.newFinder(FinderFactory.java:267)
        at org.apache.openejb.config.FinderFactory.create(FinderFactory.java:80)
        at org.apache.openejb.config.FinderFactory.createFinder(FinderFactory.java:69)
        at org.apache.openejb.config.DeploymentLoader.addWebModule(DeploymentLoader.java:878)
        ... 18 more

I have googled a lot about it and I found out that a possible issue might be that there is a conflict with scanners, because Swagger jaxrs2 dependency has its own jaxrs2 annotation and resource scanner and also Tomee has its own scanner for java 8 sources. Unfortunatelly I did not manage to find a solution how to solve this conflict and I do not have experience with annotation and resource scanners in Java.

Those are the dependencies that cause the my-rest-api.war fail while Tomee tries to deploy it:

        <!-- Swagger -->
        <dependency>
            <groupId>io.swagger.core.v3</groupId>
            <artifactId>swagger-jaxrs2</artifactId>
            <scope>compile</scope>
            <version>${swagger.jaxrs2.version}</version>
        </dependency>
        <dependency>
            <groupId>io.swagger.core.v3</groupId>
            <artifactId>swagger-jaxrs2-servlet-initializer</artifactId>
            <version>${swagger.jaxrs2.version}</version>
        </dependency>

I am looking for a solution to add those dependencies to the project and not make the deployment on Tomee fail due to this. I need those dependencies for swagger v3 annotations to document the Rest API code.

Answer 1

Ok I have just found out that this issue is gone on Apache Tomee Plume 7.1.1 and 8.0.0. So updating the Tomee server is a solution.