菜鸟入门 第一次配置 log4j 遇到如下问题，不知啥意思， 请教各前辈.....不胜感激
严重: Error deploying web application directory Test
java.lang.NoSuchFieldError: DEBUG
at org.apache.commons.logging.impl.Log4JLogger.debug(Log4JLogger.java:137)
at org.apache.tomcat.util.digester.Digester.setDocumentLocator(Digester.java:1171)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.startDocument(AbstractSAXParser.java:282)
at com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator.startDocument(XMLDTDValidator.java:663)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.startEntity(XMLDocumentScannerImpl.java:585)
at com.sun.org.apache.xerces.internal.impl.XMLVersionDetector.startDocumentParsing(XMLVersionDetector.java:172)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:785)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:737)
at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:107)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1205)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:522)
at org.apache.tomcat.util.digester.Digester.parse(Digester.java:1562)
at org.apache.catalina.startup.ContextConfig.processDefaultWebConfig(ContextConfig.java:677)
at org.apache.catalina.startup.ContextConfig.defaultWebConfig(ContextConfig.java:614)
at org.apache.catalina.startup.ContextConfig.start(ContextConfig.java:1043)
at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:261)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:120)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4148)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:760)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:740)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:544)
at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:920)
at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:883)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:492)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1138)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:311)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:120)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1022)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:736)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1014)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:443)
at org.apache.catalina.core.StandardService.start(StandardService.java:448)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:700)
at org.apache.catalina.startup.Catalina.start(Catalina.java:552)
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.apache.catalina.startup.Bootstrap.start(Bootstrap.java:295)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:433)