报错情况：
严重: Null component Catalina:type=JspMonitor,name=jsp,..J2EEApplication=none,J2EE
2010-1-7 10:20:53 org.apache.catalina.core.AprLifecycleListener init信息: The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path:
D:/J2EE/MyEclipse Blue 7.0 M2/bin;D:/J2EE/Apache Software Foundation/Tomcat 6.0/bin2010-1-7 10:20:53 org.apache.coyote.http11.Http11Protocol init信息: Initializing Coyote HTTP/1.1 on http-80802010-1-7 10:20:53 org.apache.catalina.startup.Catalina load信息: Initialization processed in 882 ms2010-1-7 10:20:53 org.apache.catalina.core.StandardService start信息: Starting service Catalina2010-1-7 10:20:53 org.apache.catalina.core.StandardEngine start信息: Starting Servlet Engine: Apache Tomcat/6.0.162010-1-7 10:20:55 org.apache.tomcat.util.modeler.Registry registerComponent严重: Null component Catalina:type=JspMonitor,name=jsp,WebModule=//localhost/nxyc,J2EEApplication=none,J2EEServer=none2010-1-7 10:20:55 org.apache.catalina.startup.HostConfig deployDirectory严重: Error deploying web application directory nxycjava.lang.UnsupportedClassVersionError: Bad version number in .class file at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(Unknown Source) at java.security.SecureClassLoader.defineClass(Unknown Source) at org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:1819) at org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:872) at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1327) at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1206) at org.apache.catalina.startup.WebAnnotationSet.loadClassAnnotation(WebAnnotationSet.java:145) at org.apache.catalina.startup.WebAnnotationSet.loadApplicationFilterAnnotations(WebAnnotationSet.java:84) at org.apache.catalina.startup.WebAnnotationSet.loadApplicationAnnotations(WebAnnotationSet.java:57) at org.apache.catalina.startup.ContextConfig.applicationAnnotationsConfig(ContextConfig.java:297) at org.apache.catalina.startup.ContextConfig.start(ContextConfig.java:1064) at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:261) at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117) at org.apache.catalina.core.StandardContext.start(StandardContext.java:4252) 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:525) at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:924) at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:887) at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:492) at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1147) at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:311) at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117) at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1053) at org.apache.catalina.core.StandardHost.start(StandardHost.java:719) at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045) at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:443) at org.apache.catalina.core.StandardService.start(StandardService.java:516) at org.apache.catalina.core.StandardServer.start(StandardServer.java:710) at org.apache.catalina.startup.Catalina.start(Catalina.java:578) 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:288) at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:413)2010-1-7 10:20:56 org.apache.coyote.http11.Http11Protocol start信息: Starting Coyote HTTP/1.1 on http-80802010-1-7 10:20:56 org.apache.jk.common.ChannelSocket init信息: JK: ajp13 listening on /0.0.0.0:80092010-1-7 10:20:56 org.apache.jk.server.JkMain start信息: Jk running ID=0 time=0/47 config=null2010-1-7 10:20:56 org.apache.catalina.startup.Catalina start信息: Server startup in 2427 ms
解决办法：
1.打开MyEclipse2.Window3.Preferences4.选择Java节点5.Installed JREs6.可以看到当前使用的JVM是什么版本，路径在哪里，现在我们要改正和Tomcat一样的虚拟机.6.Edit7.JRE home directory8.Browse 找到:C:/Sun/SDK/jdk/jre(找到你的安装目录)9.ok搞定了.!
分析:比如，你項目中的是JRE5.0但compile是JRE6.0則出現上述錯誤。或者版本不一致!
如果工程原来是jre1.5编译的，换到一个新的MyEclipse版本需要维持用1.5,不能是1.6等，修改办法：window-->preferences-->Java-->Compiler-->Compiler compience level将1.6改成1.5
本人出现的问题属于编译器版本的更改，以前工程在MyEclipse6.0里面，用的是1.5，现在导入到MyEclipse7.0/8.0 M中，编译器默认是1.6故出现无法运行的情况，按照上面的步
骤修改，重新编译部署运行success.
