java.lang.UnsupportedClassVersionError: Bad version number in .class file (unable to load class org.apache.commons.lang3.StringUtils)
at org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:2858)
at org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:1159)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1647)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1526)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.register(XmlConfigurationProvider.java:213)
at org.apache.struts2.config.StrutsXmlConfigurationProvider.register(StrutsXmlConfigurationProvider.java:102)
at com.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer(DefaultConfiguration.java:240)
at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:67)
at org.apache.struts2.dispatcher.Dispatcher.getContainer(Dispatcher.java:967)
at org.apache.struts2.dispatcher.Dispatcher.init_PreloadConfiguration(Dispatcher.java:435)
at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:479)
at org.apache.struts2.dispatcher.ng.InitOperations.initDispatcher(InitOperations.java:74)
at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.init(StrutsPrepareAndExecuteFilter.java:57)
at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:295)
at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:424)
at org.apache.catalina.core.ApplicationFilterConfig.(ApplicationFilterConfig.java:115)
at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4076)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4730)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:799)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:779)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:583)
at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1079)
at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:1002)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:506)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1317)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:324)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:142)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1065)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:822)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1057)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:463)
at org.apache.catalina.core.StandardService.start(StandardService.java:525)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:754)
at org.apache.catalina.startup.Catalina.start(Catalina.java:595)
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:289)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:414)
2015-6-23 0:31:26 org.apache.catalina.core.StandardContext start
嚴重: Error filterStart
下面是java文檔中對UnsupportedClassVersionError的說明，說的已經很明確了！
public class UnsupportedClassVersionError extends ClassFormatError當 Java 虛擬機試圖讀取一個類文件，並確定文件的主輔版本號不受支持時，拋出該錯誤。
從以下版本開始：
1.2
