Thanks, Marek, that got me a big step further :-)
Now I do get a strange Exception where I do not have any idea about the cause
10:36:54,716 ERROR [org.jboss.msc.service.fail] (MSC service thread 1-6) MSC000001: Failed to start service jboss.undertow.deployment.default-server.default-host./TestForSeam222: org.jboss.msc.service.StartException in service jboss.undertow.deployment.default-server.default-host./TestForSeam222: Failed to start service
at org.jboss.msc.service.ServiceControllerImpl$StartTask.run(ServiceControllerImpl.java:1904) [jboss-msc-1.2.0.Final.jar:1.2.0.Final]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [rt.jar:1.7.0_60]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [rt.jar:1.7.0_60]
at java.lang.Thread.run(Thread.java:745) [rt.jar:1.7.0_60]
Caused by: java.lang.RuntimeException: org.jboss.seam.InstantiationException: Could not instantiate Seam component: org.jboss.seam.resteasy.bootstrap
at io.undertow.servlet.core.DeploymentManagerImpl.deploy(DeploymentManagerImpl.java:216)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentService.startContext(UndertowDeploymentService.java:86)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentService.start(UndertowDeploymentService.java:71)
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]
... 3 more
Caused by: org.jboss.seam.InstantiationException: Could not instantiate Seam component: org.jboss.seam.resteasy.bootstrap
at org.jboss.seam.Component.newInstance(Component.java:2170)
at org.jboss.seam.contexts.Contexts.startup(Contexts.java:304)
at org.jboss.seam.contexts.Contexts.startup(Contexts.java:278)
at org.jboss.seam.contexts.ServletLifecycle.endInitialization(ServletLifecycle.java:143)
at org.jboss.seam.init.Initialization.init(Initialization.java:744)
at org.jboss.seam.servlet.SeamListener.contextInitialized(SeamListener.java:36)
at io.undertow.servlet.core.ApplicationListeners.contextInitialized(ApplicationListeners.java:173)
at io.undertow.servlet.core.DeploymentManagerImpl.deploy(DeploymentManagerImpl.java:187)
... 7 more
Caused by: java.lang.RuntimeException: exception invoking: init
at org.jboss.seam.util.Reflections.invokeAndWrap(Reflections.java:154)
at org.jboss.seam.Component.callComponentMethod(Component.java:2275)
at org.jboss.seam.Component.callCreateMethod(Component.java:2198)
at org.jboss.seam.Component.newInstance(Component.java:2158)
... 14 more
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [rt.jar:1.7.0_60]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) [rt.jar:1.7.0_60]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) [rt.jar:1.7.0_60]
at java.lang.reflect.Method.invoke(Method.java:606) [rt.jar:1.7.0_60]
at org.jboss.seam.util.Reflections.invoke(Reflections.java:22)
at org.jboss.seam.intercept.RootInvocationContext.proceed(RootInvocationContext.java:32)
at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:56)
at org.jboss.seam.transaction.RollbackInterceptor.aroundInvoke(RollbackInterceptor.java:28)
at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
at org.jboss.seam.core.BijectionInterceptor.aroundInvoke(BijectionInterceptor.java:77)
at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
at org.jboss.seam.core.MethodContextInterceptor.aroundInvoke(MethodContextInterceptor.java:44)
at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
at org.jboss.seam.intercept.RootInterceptor.invoke(RootInterceptor.java:107)
at org.jboss.seam.intercept.JavaBeanInterceptor.interceptInvocation(JavaBeanInterceptor.java:185)
at org.jboss.seam.intercept.JavaBeanInterceptor.invoke(JavaBeanInterceptor.java:103)
at org.jboss.seam.resteasy.ResteasyBootstrap_$$_javassist_seam_1.init(ResteasyBootstrap_$$_javassist_seam_1.java)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [rt.jar:1.7.0_60]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) [rt.jar:1.7.0_60]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) [rt.jar:1.7.0_60]
at java.lang.reflect.Method.invoke(Method.java:606) [rt.jar:1.7.0_60]
at org.jboss.seam.util.Reflections.invoke(Reflections.java:22)
at org.jboss.seam.util.Reflections.invokeAndWrap(Reflections.java:144)
... 17 more
Caused by: java.lang.NoSuchMethodError: org.jboss.resteasy.core.Dispatcher.setLanguageMappings(Ljava/util/Map;)V
at org.jboss.seam.resteasy.ResteasyBootstrap.initDispatcher(ResteasyBootstrap.java:148)
at org.jboss.seam.resteasy.ResteasyBootstrap.init(ResteasyBootstrap.java:110)
... 40 more
10:36:54,727 ERROR [org.jboss.as.controller.management-operation] (DeploymentScanner-threads - 2) JBAS014613: Operation ("deploy") failed - address: ([("deployment" => "TestForSeam222.war")]) - failure description: {"JBAS014671: Failed services" => {"jboss.undertow.deployment.default-server.default-host./TestForSeam222" => "org.jboss.msc.service.StartException in service jboss.undertow.deployment.default-server.default-host./TestForSeam222: Failed to start service
Caused by: java.lang.RuntimeException: org.jboss.seam.InstantiationException: Could not instantiate Seam component: org.jboss.seam.resteasy.bootstrap
Caused by: org.jboss.seam.InstantiationException: Could not instantiate Seam component: org.jboss.seam.resteasy.bootstrap
Caused by: java.lang.RuntimeException: exception invoking: init
Caused by: java.lang.reflect.InvocationTargetException
Caused by: java.lang.NoSuchMethodError: org.jboss.resteasy.core.Dispatcher.setLanguageMappings(Ljava/util/Map;)V"}}
Thanks again for helping me