title: SEVERE: A child container failed during start tomcat8
body: <p>I wrote a simple sevlet program. When I am trying to deploy the same in tomcat I am getting the below error.</p>
  
  <p>I have tried by removing annotations. </p>
  
  <pre><code>SEVERE: A child container failed during start
  java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/Trial]]
   at java.util.concurrent.FutureTask.report(Unknown Source)
   at java.util.concurrent.FutureTask.get(Unknown Source)
   at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:916)
   at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:868)
   at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
   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(Unknown Source)
   at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
   at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
   at java.lang.Thread.run(Unknown Source)
  Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/Trial]]
   at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
   ... 6 more
  Caused by: java.lang.IllegalArgumentException: Invalid &lt;url-pattern&gt; firstTest in servlet mapping
   at org.apache.catalina.core.StandardContext.addServletMapping(StandardContext.java:3104)
   at org.apache.catalina.core.StandardContext.addServletMapping(StandardContext.java:3079)
   at org.apache.catalina.startup.ContextConfig.configureContext(ContextConfig.java:1368)
   at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1172)
   at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:767)
   at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:302)
   at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
   at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
   at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5074)
   at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
   ... 6 more
  
  Sep 19, 2014 9:51:45 PM org.apache.catalina.core.ContainerBase startInternal
  SEVERE: 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(Unknown Source)
   at java.util.concurrent.FutureTask.get(Unknown Source)
   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:150)
   at org.apache.catalina.core.StandardService.startInternal(StandardService.java:439)
   at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
   at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:760)
   at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
   at org.apache.catalina.startup.Catalina.start(Catalina.java:625)
   at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
   at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
   at java.lang.reflect.Method.invoke(Unknown Source)
   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:154)
   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(Unknown Source)
   at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
   at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
   at java.lang.Thread.run(Unknown Source)
  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:868)
   at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
   ... 6 more
  
  Sep 19, 2014 9:51:45 PM org.apache.catalina.startup.Catalina start
  SEVERE: 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:154)
   at org.apache.catalina.startup.Catalina.start(Catalina.java:625)
   at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
   at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
   at java.lang.reflect.Method.invoke(Unknown Source)
   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:154)
   at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:760)
   at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
   ... 7 more
  Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina]]
   at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
   at org.apache.catalina.core.StandardService.startInternal(StandardService.java:439)
   at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
   ... 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:150)
   ... 11 more
  
  Sep 19, 2014 9:51:45 PM org.apache.coyote.AbstractProtocol pause
  INFO: Pausing ProtocolHandler ["http-nio-8080"]
  Sep 19, 2014 9:51:45 PM org.apache.coyote.AbstractProtocol pause
  INFO: Pausing ProtocolHandler ["ajp-nio-8009"]
  Sep 19, 2014 9:51:45 PM org.apache.catalina.core.StandardService stopInternal
  INFO: Stopping service Catalina
  Sep 19, 2014 9:51:45 PM org.apache.coyote.AbstractProtocol destroy
  INFO: Destroying ProtocolHandler ["http-nio-8080"]
  Sep 19, 2014 9:51:45 PM org.apache.coyote.AbstractProtocol destroy
  SEVERE: Failed to destroy end point associated with ProtocolHandler ["http-nio-8080"]
  java.lang.NullPointerException
   at org.apache.tomcat.util.net.NioEndpoint.releaseCaches(NioEndpoint.java:307)
   at org.apache.tomcat.util.net.NioEndpoint.unbind(NioEndpoint.java:482)
   at org.apache.tomcat.util.net.AbstractEndpoint.destroy(AbstractEndpoint.java:795)
   at org.apache.coyote.AbstractProtocol.destroy(AbstractProtocol.java:531)
   at org.apache.catalina.connector.Connector.destroyInternal(Connector.java:1023)
   at org.apache.catalina.util.LifecycleBase.destroy(LifecycleBase.java:305)
   at org.apache.catalina.core.StandardService.destroyInternal(StandardService.java:588)
   at org.apache.catalina.util.LifecycleBase.destroy(LifecycleBase.java:305)
   at org.apache.catalina.core.StandardServer.destroyInternal(StandardServer.java:850)
   at org.apache.catalina.util.LifecycleBase.destroy(LifecycleBase.java:305)
   at org.apache.catalina.startup.Catalina.start(Catalina.java:629)
   at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
   at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
   at sun.reflect.DelegatingMethodAcc
  </code></pre>
  
  <p>servlet code is below. the server is starting fine without the application</p>
  
  <pre><code>import java.io.IOException;
  import javax.servlet.ServletException;
  import javax.servlet.annotation.WebServlet;
  import javax.servlet.http.HttpServlet;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  
  /**
   * Servlet implementation class MyServlet
   */
  
  public class MyServlet extends HttpServlet {
   private static final long serialVersionUID = 1L;
  
      /**
       * Default constructor. 
       */
      public MyServlet() {
          // TODO Auto-generated constructor stub
      }
  
   /**
    * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
    */
   protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    // TODO Auto-generated method stub
   }
  
   /**
    * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
    */
   protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    // TODO Auto-generated method stub
   }
  
  }
  </code></pre>