How to debug ClassNotFoundException: org.apache.struts2.tiles.StrutsTilesListener?

The error:

2016-04-12 12:32:04,399 INFO  [org.hibernate.tool.hbm2ddl.SchemaExport] (ServerService Thread Pool -- 62) HHH000230: Schema export complete
2016-04-12 12:32:04,753 ERROR [org.jboss.msc.service.fail] (MSC service thread 1-5) MSC000001: Failed to start service jboss.undertow.deployment.default-server.default-host./BanqueEEWeb.UndertowDeploymentInfoService: org.jboss.msc.service.StartException in service jboss.undertow.deployment.default-server.default-host./BanqueEEWeb.UndertowDeploymentInfoService: java.lang.ClassNotFoundException: org.apache.struts2.tiles.StrutsTilesListener from [Module "deployment.BanqueEE.ear.BanqueEEWeb.war:main" from Service Module Loader]
    at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService.createServletConfig(UndertowDeploymentInfoService.java:870)
    at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService.start(UndertowDeploymentInfoService.java:242)
    at org.jboss.msc.service.ServiceControllerImpl$StartTask.startService(ServiceControllerImpl.java:1948) [jboss-msc-1.2.0.Final.jar:1.2.0.Final]
    at org.jboss.msc.service.ServiceControllerImpl$StartTask.run(ServiceControllerImpl.java:1881) [jboss-msc-1.2.0.Final.jar:1.2.0.Final]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) [rt.jar:1.8.0_66]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) [rt.jar:1.8.0_66]
    at java.lang.Thread.run(Unknown Source) [rt.jar:1.8.0_66]
Caused by: java.lang.ClassNotFoundException: org.apache.struts2.tiles.StrutsTilesListener from [Module "deployment.BanqueEE.ear.BanqueEEWeb.war:main" from Service Module Loader]
    at org.jboss.modules.ModuleClassLoader.findClass(ModuleClassLoader.java:197) [jboss-modules.jar:1.3.0.Final]
    at org.jboss.modules.ConcurrentClassLoader.performLoadClassUnchecked(ConcurrentClassLoader.java:443) [jboss-modules.jar:1.3.0.Final]
    at org.jboss.modules.ConcurrentClassLoader.performLoadClassChecked(ConcurrentClassLoader.java:431) [jboss-modules.jar:1.3.0.Final]
    at org.jboss.modules.ConcurrentClassLoader.performLoadClass(ConcurrentClassLoader.java:373) [jboss-modules.jar:1.3.0.Final]
    at org.jboss.modules.ConcurrentClassLoader.loadClass(ConcurrentClassLoader.java:118) [jboss-modules.jar:1.3.0.Final]
    at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService.addListener(UndertowDeploymentInfoService.java:1145)
    at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService.createServletConfig(UndertowDeploymentInfoService.java:734)
    ... 6 more

2016-04-12 12:32:05,109 INFO  [org.jboss.weld.Bootstrap] (weld-worker-4) WELD-000119: Not generating any bean definitions from org.apache.struts2.tiles.StrutsTilesListener because of underlying class loading error: Type org.apache.struts2.tiles.StrutsTilesListener from [Module "deployment.BanqueEE.ear.BanqueEEWeb.war:main" from Service Module Loader] not found.  If this is unexpected, enable DEBUG logging to see the full error.
2016-04-12 12:32:07,323 ERROR [org.jboss.as.controller.management-operation] (Controller Boot Thread) JBAS014613: Operation ("deploy") failed - address: ([("deployment" => "BanqueEE.ear")]) - failure description: {"JBAS014671: Failed services" => {"jboss.undertow.deployment.default-server.default-host./BanqueEEWeb.UndertowDeploymentInfoService" => "org.jboss.msc.service.StartException in service jboss.undertow.deployment.default-server.default-host./BanqueEEWeb.UndertowDeploymentInfoService: java.lang.ClassNotFoundException: org.apache.struts2.tiles.StrutsTilesListener from [Module \"deployment.BanqueEE.ear.BanqueEEWeb.war:main\" from Service Module Loader]
    Caused by: java.lang.ClassNotFoundException: org.apache.struts2.tiles.StrutsTilesListener from [Module \"deployment.BanqueEE.ear.BanqueEEWeb.war:main\" from Service Module Loader]"}}
2016-04-12 12:32:07,408 INFO  [org.jboss.as.server] (ServerService Thread Pool -- 34) JBAS018559: Deployed "BanqueEE.ear" (runtime-name : "BanqueEE.ear")
2016-04-12 12:32:07,410 INFO  [org.jboss.as.controller] (Controller Boot Thread) JBAS014774: Service status report
JBAS014777:   Services which failed to start:      service jboss.undertow.deployment.default-server.default-host./BanqueEEWeb.UndertowDeploymentInfoService: org.jboss.msc.service.StartException in service jboss.undertow.deployment.default-server.default-host./BanqueEEWeb.UndertowDeploymentInfoService: java.lang.ClassNotFoundException: org.apache.struts2.tiles.StrutsTilesListener from [Module "deployment.BanqueEE.ear.BanqueEEWeb.war:main" from Service Module Loader]

How to debug this error in Struts 2?

You have missed a library struts2-tiles-plugin-x.x.x.x.jar and probably their dependencies.

What you need is to add these libraries to the Deployment Assembly. It will help you to archive ear project and include dependencies that have equivalent manifest settings in their classpath.

If you want to know what is a Deployment Assembly you can read this article Eclipse : Java EE Module Dependencies is replaced by Web Deployment Assembly.

“Web Deployment Assembly“, which provide more powerful and flexible ways to configure the project packaging structure.

There's also a page that describes the process of linking external resources with the ear application: Web Application Development: Configuring Projects with External Resources.