Java.lang.UnsupportedClassVersionError:Bad version number in. class file, unable to load class org.

1. Error description

Severity: Exception Starting filter Struts2java.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:2737) at Org.apache.catalina.loader.WebappClassLoader.findClass (Webappclassloader.java : 1124) at Org.apache.catalina.loader.WebappClassLoader.loadClass (webappclassloader.java:1612) at Org.apache.catalina.loader.WebappClassLoader.loadClass (webappclassloader.java:1491) 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.StrutsPrepareFilter.init (strutspreparefilter.java:56) at Org.apache.catalina.core.ApplicationFilterConfig.getFilter (applicationfilterconfig.java:295) at Org.apache.catalina.core.ApplicationFilterConfig.setFilterDef (applicationfilterconfig.java:422) at Org.apache.catalina.core.applicationfilterconfig.<init> (applicationfilterconfig.java:115) at Org.apache.catalina.core.StandardContext.filterStart (standardcontext.java:4001) at Org.apache.catalina.core.StandardContext.start (standardcontext.java:4651) at Org.apache.catalina.core.ContainerBase.addChildInternal (containerbase.java:791) at Org.apache.catalina.core.ContainerBasE.addchild (containerbase.java:771) at Org.apache.catalina.core.StandardHost.addChild (standardhost.java:546) at Org.apache.catalina.startup.HostConfig.deployDirectory (hostconfig.java:1041) at Org.apache.catalina.startup.HostConfig.deployDirectories (hostconfig.java:964) at Org.apache.catalina.startup.HostConfig.deployApps (hostconfig.java:502) at Org.apache.catalina.startup.HostConfig.start (hostconfig.java:1277) at Org.apache.catalina.startup.HostConfig.lifecycleEvent (hostconfig.java:321) at Org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent (lifecyclesupport.java:119) at Org.apache.catalina.core.ContainerBase.start (containerbase.java:1053) at Org.apache.catalina.core.StandardHost.start (standardhost.java:785) at Org.apache.catalina.core.ContainerBase.start (containerbase.java:1045) at Org.apache.catalina.core.StandardEngine.start (standardengine.java:445) at Org.apache.catalina.core.StandardService.start (standardservice.java:519) at Org.apache.catalina.core.StandardServer.start (STANDARDSERVER.Java:710) at Org.apache.catalina.startup.Catalina.start (catalina.java:581) 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) 2015-4-12 9:26:20 Org.apache.catalina.core.StandardContext start severity: Error filterstart2015-4-12 9:26:20 Org.apache.catalina.core.StandardContext start severity: Context [/fusioncharts] startup failed due to previous errors

2. Cause of Error

Previously created projects are JDK7, and later deployed with JDK6, resulting in an error

3. Solutions

Ensure the JDK version of the project is consistent and deploy the project with JDK7

Java.lang.UnsupportedClassVersionError:Bad version number in. class file, unable to load class org.