A child container failed during start

error starting Tomcat, complete information is as follows:

严重: A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/WIcket-Learn]]
	at java.util.concurrent.FutureTask.report(FutureTask.java:122)
	at java.util.concurrent.FutureTask.get(FutureTask.java:188)
	at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:916)
	at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:871)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1408)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1398)
	at java.util.concurrent.FutureTask.run(FutureTask.java:262)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:745)
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/WIcket-Learn]]
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:153)
	... 6 more
Caused by: java.lang.IllegalArgumentException: Filter mapping specifies an unknown filter name DempApplication
	at org.apache.catalina.core.StandardContext.validateFilterMap(StandardContext.java:2944)
	at org.apache.catalina.core.StandardContext.addFilterMap(StandardContext.java:2909)
	at org.apache.catalina.startup.ContextConfig.configureContext(ContextConfig.java:1275)
	at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1184)
	at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:779)
	at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:306)
	at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:95)
	at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
	at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5150)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
	... 6 more

五月 03, 2017 4:06:10 下午 org.apache.catalina.core.ContainerBase startInternal
严重: A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost]]
	at java.util.concurrent.FutureTask.report(FutureTask.java:122)
	at java.util.concurrent.FutureTask.get(FutureTask.java:188)
	at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:916)
	at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:262)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
	at org.apache.catalina.core.StandardService.startInternal(StandardService.java:441)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
	at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:787)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
	at org.apache.catalina.startup.Catalina.start(Catalina.java:629)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:351)
	at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:485)
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost]]
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:153)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1408)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1398)
	at java.util.concurrent.FutureTask.run(FutureTask.java:262)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:745)
Caused by: org.apache.catalina.LifecycleException: A child container failed during start
	at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:924)
	at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:871)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
	... 6 more

五月 03, 2017 4:06:10 下午 org.apache.catalina.startup.Catalina start
严重: The required Server component failed to start so Tomcat is unable to start.
org.apache.catalina.LifecycleException: Failed to start component [StandardServer[8005]]
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:153)
	at org.apache.catalina.startup.Catalina.start(Catalina.java:629)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:351)
	at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:485)
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardService[Catalina]]
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:153)
	at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:787)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
	... 7 more
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina]]
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:153)
	at org.apache.catalina.core.StandardService.startInternal(StandardService.java:441)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
	... 9 more
Caused by: org.apache.catalina.LifecycleException: A child container failed during start
	at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:924)
	at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:262)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
	... 11 more

五月 03, 2017 4:06:10 下午 org.apache.coyote.AbstractProtocol pause
信息: Pausing ProtocolHandler ["http-nio-8080"]
五月 03, 2017 4:06:10 下午 org.apache.coyote.AbstractProtocol pause
信息: Pausing ProtocolHandler ["ajp-nio-8009"]
五月 03, 2017 4:06:10 下午 org.apache.catalina.core.StandardService stopInternal
信息: Stopping service Catalina
五月 03, 2017 4:06:10 下午 org.apache.coyote.AbstractProtocol destroy
信息: Destroying ProtocolHandler ["http-nio-8080"]
五月 03, 2017 4:06:10 下午 org.apache.coyote.AbstractProtocol destroy
严重: Failed to destroy end point associated with ProtocolHandler ["http-nio-8080"]
java.lang.NullPointerException
	at org.apache.tomcat.util.net.NioEndpoint.releaseCaches(NioEndpoint.java:305)
	at org.apache.tomcat.util.net.NioEndpoint.unbind(NioEndpoint.java:481)
	at org.apache.tomcat.util.net.AbstractEndpoint.destroy(AbstractEndpoint.java:831)
	at org.apache.coyote.AbstractProtocol.destroy(AbstractProtocol.java:533)
	at org.apache.catalina.connector.Connector.destroyInternal(Connector.java:1023)
	at org.apache.catalina.util.LifecycleBase.destroy(LifecycleBase.java:297)
	at org.apache.catalina.core.StandardService.destroyInternal(StandardService.java:589)
	at org.apache.catalina.util.LifecycleBase.destroy(LifecycleBase.java:297)
	at org.apache.catalina.core.StandardServer.destroyInternal(StandardServer.java:877)
	at org.apache.catalina.util.LifecycleBase.destroy(LifecycleBase.java:297)
	at org.apache.catalina.startup.Catalina.start(Catalina.java:633)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:351)
	at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:485)

五月 03, 2017 4:06:10 下午 org.apache.coyote.AbstractProtocol destroy
信息: Destroying ProtocolHandler ["ajp-nio-8009"]
五月 03, 2017 4:06:10 下午 org.apache.coyote.AbstractProtocol destroy
严重: Failed to destroy end point associated with ProtocolHandler ["ajp-nio-8009"]
java.lang.NullPointerException
	at org.apache.tomcat.util.net.NioEndpoint.releaseCaches(NioEndpoint.java:305)
	at org.apache.tomcat.util.net.NioEndpoint.unbind(NioEndpoint.java:481)
	at org.apache.tomcat.util.net.AbstractEndpoint.destroy(AbstractEndpoint.java:831)
	at org.apache.coyote.AbstractProtocol.destroy(AbstractProtocol.java:533)
	at org.apache.catalina.connector.Connector.destroyInternal(Connector.java:1023)
	at org.apache.catalina.util.LifecycleBase.destroy(LifecycleBase.java:297)
	at org.apache.catalina.core.StandardService.destroyInternal(StandardService.java:589)
	at org.apache.catalina.util.LifecycleBase.destroy(LifecycleBase.java:297)
	at org.apache.catalina.core.StandardServer.destroyInternal(StandardServer.java:877)
	at org.apache.catalina.util.LifecycleBase.destroy(LifecycleBase.java:297)
	at org.apache.catalina.startup.Catalina.start(Catalina.java:633)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:351)
	at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:485)

Finally, I checked that the filter mapping name was misspelled

<filter>
  	<filter-name>DemoApplication</filter-name>
  	<filter-class>org.apache.wicket.protocol.http.WicketFilter</filter-class>
  		<init-param>
				<param-name>applicationClassName</param-name>
				<param-value>org.wicket.demo.BookmarkablePageLink.HelloWorldApplication</param-value>  			
  		</init-param>
  </filter>
  
  <filter-mapping>
  	<filter-name>DempApplication</filter-name>
  	<url-pattern>/*</url-pattern>
  </filter-mapping>


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