アプリを JBOSS5 にデプロイしている間 (以前は JBOSS4 にデプロイしていました)、以下の例外が発生します。
このエラーは、struts で使用される com.opensymphony.xwork2 パッケージと関係があると思います。
java.lang.LinkageError: loader constraint violation: when resolving method "javax.xml.parsers.DocumentBuilder.setErrorHandler(Lorg/xml/sax/ErrorHandler;)V" the class loader (instance of org/jboss/classloader/spi/base/BaseClassLoader) of the current class, org/apache/log4j/xml/DOMConfigurator, and the class loader (instance of <bootloader>) for resolved class, javax/xml/parsers/DocumentBuilder, have different Class objects for the type org/xml/sax/ErrorHandler used in the signature
at org.apache.log4j.xml.DOMConfigurator.doConfigure(DOMConfigurator.java:708)
at org.apache.log4j.xml.DOMConfigurator.doConfigure(DOMConfigurator.java:618)
at org.apache.log4j.helpers.OptionConverter.selectAndConfigure(OptionConverter.java:470)
at org.apache.log4j.LogManager.<clinit>(LogManager.java:122)
at org.apache.log4j.Logger.getLogger(Logger.java:117)
at com.hmco.ssms.servlet.filter.AuthFilter.<clinit>(AuthFilter.java:38)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at java.lang.Class.newInstance0(Class.java:355)
at java.lang.Class.newInstance(Class.java:308)
at org.jboss.web.tomcat.service.TomcatInjectionContainer.newInstance(TomcatInjectionContainer.java:264)
at org.jboss.web.tomcat.service.TomcatInjectionContainer.newInstance(TomcatInjectionContainer.java:256)
at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:220)
at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:332)
at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:90)
at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:3783)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4413)
at org.jboss.web.tomcat.service.deployers.TomcatDeployment.performDeployInternal(TomcatDeployment.java:310)
at org.jboss.web.tomcat.service.deployers.TomcatDeployment.performDeploy(TomcatDeployment.java:142)
at org.jboss.web.deployers.AbstractWarDeployment.start(AbstractWarDeployment.java:461)
at org.jboss.web.deployers.WebModule.startModule(WebModule.java:118)
at org.jboss.web.deployers.WebModule.start(WebModule.java:97)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:157)
at org.jboss.mx.server.Invocation.dispatch(Invocation.java:96)
at org.jboss.mx.server.Invocation.invoke(Invocation.java:88)
at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264)
at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:668)
at org.jboss.system.microcontainer.ServiceProxy.invoke(ServiceProxy.java:206)
at $Proxy38.start(Unknown Source)
at org.jboss.system.microcontainer.StartStopLifecycleAction.installAction(StartStopLifecycleAction.java:42)
at org.jboss.system.microcontainer.StartStopLifecycleAction.installAction(StartStopLifecycleAction.java:37)
at org.jboss.dependency.plugins.action.SimpleControllerContextAction.simpleInstallAction(SimpleControllerContextAction.java:62)
at org.jboss.dependency.plugins.action.AccessControllerContextAction.install(AccessControllerContextAction.java:71)
at org.jboss.dependency.plugins.AbstractControllerContextActions.install(AbstractControllerContextActions.java:51)
at org.jboss.dependency.plugins.AbstractControllerContext.install(AbstractControllerContext.java:348)
at org.jboss.system.microcontainer.ServiceControllerContext.install(ServiceControllerContext.java:286)
at org.jboss.dependency.plugins.AbstractController.install(AbstractController.java:1631)
at org.jboss.dependency.plugins.AbstractController.incrementState(AbstractController.java:934)
at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:1082)
at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:984)
at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:822)
at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:553)
at org.jboss.system.ServiceController.doChange(ServiceController.java:688)
at org.jboss.system.ServiceController.start(ServiceController.java:460)
at org.jboss.system.deployers.ServiceDeployer.start(ServiceDeployer.java:163)
at org.jboss.system.deployers.ServiceDeployer.deploy(ServiceDeployer.java:99)
at org.jboss.system.deployers.ServiceDeployer.deploy(ServiceDeployer.java:46)
at org.jboss.deployers.spi.deployer.helpers.AbstractSimpleRealDeployer.internalDeploy(AbstractSimpleRealDeployer.java:62)
at org.jboss.deployers.spi.deployer.helpers.AbstractRealDeployer.deploy(AbstractRealDeployer.java:50)
at org.jboss.deployers.plugins.deployers.DeployerWrapper.deploy(DeployerWrapper.java:171)
at org.jboss.deployers.plugins.deployers.DeployersImpl.doDeploy(DeployersImpl.java:1439)
at org.jboss.deployers.plugins.deployers.DeployersImpl.doInstallParentFirst(DeployersImpl.java:1157)
at org.jboss.deployers.plugins.deployers.DeployersImpl.doInstallParentFirst(DeployersImpl.java:1178)
at org.jboss.deployers.plugins.deployers.DeployersImpl.doInstallParentFirst(DeployersImpl.java:1210)
at org.jboss.deployers.plugins.deployers.DeployersImpl.install(DeployersImpl.java:1098)
at org.jboss.dependency.plugins.AbstractControllerContext.install(AbstractControllerContext.java:348)
at org.jboss.dependency.plugins.AbstractController.install(AbstractController.java:1631)
at org.jboss.dependency.plugins.AbstractController.incrementState(AbstractController.java:934)
at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:1082)
at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:984)
at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:822)
at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:553)
at org.jboss.deployers.plugins.deployers.DeployersImpl.process(DeployersImpl.java:781)
at org.jboss.deployers.plugins.main.MainDeployerImpl.process(MainDeployerImpl.java:702)
at org.jboss.system.server.profileservice.repository.MainDeployerAdapter.process(MainDeployerAdapter.java:117)
at org.jboss.system.server.profileservice.repository.ProfileDeployAction.install(ProfileDeployAction.java:70)
at org.jboss.system.server.profileservice.repository.AbstractProfileAction.install(AbstractProfileAction.java:53)
at org.jboss.system.server.profileservice.repository.AbstractProfileService.install(AbstractProfileService.java:361)
at org.jboss.dependency.plugins.AbstractControllerContext.install(AbstractControllerContext.java:348)
at org.jboss.dependency.plugins.AbstractController.install(AbstractController.java:1631)
at org.jboss.dependency.plugins.AbstractController.incrementState(AbstractController.java:934)
at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:1082)
at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:984)
at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:822)
at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:553)
at org.jboss.system.server.profileservice.repository.AbstractProfileService.activateProfile(AbstractProfileService.java:306)
at org.jboss.system.server.profileservice.ProfileServiceBootstrap.start(ProfileServiceBootstrap.java:271)
at org.jboss.bootstrap.AbstractServerImpl.start(AbstractServerImpl.java:461)
at org.jboss.Main.boot(Main.java:221)
at org.jboss.Main$1.run(Main.java:556)
at java.lang.Thread.run(Thread.java:662)
libフォルダーからXerces、Xalan（すべてのxml API関連のjar）を削除し、EARをコンパイルしてサーバーに配置しました。しかし、まだこの例外が発生しています。
あなたの助けの友人に感謝します!!