title: java.lang.NullPointerException at com.opensymphony.xwork2.validator.AnnotationActionValidatorManager.loadFile after upgrading Struts2
body: <p>We recently upgraded the version of struts in our website from 2.1.8.1 to 2.3.4.  Immediately after upgrading we noticed the following exception after the first post back to the server.  Any help in determining the issue or how to troubleshoot this would be appreciated.  We've been scratching our head for days.  The thing that makes this really bad is when the site is deployed to websphere once this exception is thrown the site stops working completely until you restart the jvm.  In tom cat the below exception is thrown but the site continues to work.</p>
  
  <pre><code>2013-09-17 15:09:18,919 [WebContainer : 0] ERROR com.opensymphony.xwork2.validator.AnnotationActionValidatorManager - Caught exception while loading file java/lang/Object-validation.xml
  java.lang.NullPointerException
      at com.opensymphony.xwork2.validator.AnnotationActionValidatorManager.loadFile(AnnotationActionValidatorManager.java:383)
      at com.opensymphony.xwork2.validator.AnnotationActionValidatorManager.buildClassValidatorConfigs(AnnotationActionValidatorManager.java:271)
      at com.opensymphony.xwork2.validator.AnnotationActionValidatorManager.buildValidatorConfigs(AnnotationActionValidatorManager.java:363)
      at com.opensymphony.xwork2.validator.AnnotationActionValidatorManager.buildValidatorConfigs(AnnotationActionValidatorManager.java:342)
      at com.opensymphony.xwork2.validator.AnnotationActionValidatorManager.buildValidatorConfigs(AnnotationActionValidatorManager.java:342)
      at com.opensymphony.xwork2.validator.AnnotationActionValidatorManager.getValidators(AnnotationActionValidatorManager.java:94)
      at com.opensymphony.xwork2.validator.AnnotationActionValidatorManager.validate(AnnotationActionValidatorManager.java:133)
      at com.opensymphony.xwork2.validator.AnnotationActionValidatorManager.validate(AnnotationActionValidatorManager.java:125)
      at com.opensymphony.xwork2.validator.AnnotationActionValidatorManager.validate(AnnotationActionValidatorManager.java:120)
      at com.opensymphony.xwork2.validator.ValidationInterceptor.doBeforeInvocation(ValidationInterceptor.java:222)
      at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:263)
      at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68)
      at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
      at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
      at com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:138)
      at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
      at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:211)
      at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
      at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
      at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:211)
      at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
      at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
      at com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:190)
      at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
      at org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:75)
      at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
      at org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:90)
      at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
      at org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:243)
      at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
      at com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:100)
      at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
      at com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:141)
      at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
      at com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:145)
      at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
      at com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:171)
      at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
      at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
      at com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:176)
      at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
      at org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)
      at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
      at com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:192)
      at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
      at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:187)
      at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
      at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:54)
      at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:511)
      at org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:432)
      at com.ibm.ws.webcontainer.filter.FilterInstanceWrapper.doFilter(FilterInstanceWrapper.java:190)
      at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:125)
      at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:83)
      at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
      at com.ibm.ws.webcontainer.filter.FilterInstanceWrapper.doFilter(FilterInstanceWrapper.java:190)
      at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:125)
      at com.ibm.ws.webcontainer.filter.WebAppFilterChain._doFilter(WebAppFilterChain.java:80)
      at com.ibm.ws.webcontainer.filter.WebAppFilterManager.doFilter(WebAppFilterManager.java:908)
      at com.ibm.ws.webcontainer.filter.WebAppFilterManager.invokeFilters(WebAppFilterManager.java:997)
      at com.ibm.ws.webcontainer.extension.DefaultExtensionProcessor.invokeFilters(DefaultExtensionProcessor.java:1079)
      at com.ibm.ws.webcontainer.extension.DefaultExtensionProcessor.handleRequest(DefaultExtensionProcessor.java:999)
      at com.ibm.ws.webcontainer.webapp.WebApp.handleRequest(WebApp.java:3954)
      at com.ibm.ws.webcontainer.webapp.WebGroup.handleRequest(WebGroup.java:276)
      at com.ibm.ws.webcontainer.WebContainer.handleRequest(WebContainer.java:945)
      at com.ibm.ws.webcontainer.WSWebContainer.handleRequest(WSWebContainer.java:1592)
      at com.ibm.ws.webcontainer.channel.WCChannelLink.ready(WCChannelLink.java:191)
      at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleDiscrimination(HttpInboundLink.java:453)
      at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleNewRequest(HttpInboundLink.java:515)
      at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.processRequest(HttpInboundLink.java:306)
      at com.ibm.ws.http.channel.inbound.impl.HttpICLReadCallback.complete(HttpICLReadCallback.java:84)
      at com.ibm.ws.ssl.channel.impl.SSLReadServiceContext$SSLReadCompletedCallback.complete(SSLReadServiceContext.java:1784)
      at com.ibm.ws.tcp.channel.impl.AioReadCompletionListener.futureCompleted(AioReadCompletionListener.java:175)
      at com.ibm.io.async.AbstractAsyncFuture.invokeCallback(AbstractAsyncFuture.java:217)
      at com.ibm.io.async.AsyncChannelFuture.fireCompletionActions(AsyncChannelFuture.java:161)
      at com.ibm.io.async.AsyncFuture.completed(AsyncFuture.java:138)
      at com.ibm.io.async.ResultHandler.complete(ResultHandler.java:204)
      at com.ibm.io.async.ResultHandler.runEventProcessingLoop(ResultHandler.java:775)
      at com.ibm.io.async.ResultHandler$2.run(ResultHandler.java:905)
      at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java:1656)
  </code></pre>