请问下,这是什么异常,改如何解决

请问下,这是什么异常,改如何解决
java.lang.IllegalArgumentException:Invalid HelloServlet in servlet mapping
at org.apache.tomcat.util.digester.Digester.createSAXException(Digester.java:2725)
at org.apache.tomcat.util.digester.Digester.createSAXException(Digester.java:2751)
at org.apache.tomcat.util.digester.Digester.endElement(Digester.java:1060)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.endElement(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanEndElement(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(Unknown Source)
at org.apache.tomcat.util.digester.Digester.parse(Digester.java:1561)
at org.apache.catalina.startup.ContextConfig.applicationWebConfig(ContextConfig.java:351)
at org.apache.catalina.startup.ContextConfig.start(ContextConfig.java:1034)
at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:260)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4119)
at org.apache.catalina.startup.HostConfig.checkResources(HostConfig.java:1089)
at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1187)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:292)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
at org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBase.java:1305)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1569)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1578)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1558)
at java.lang.Thread.run(Unknown Source)
2009-9-24 17:39:38 org.apache.catalina.startup.ContextConfig applicationWebConfig
严重:Occurred at line 17 column 21
2009-9-24 17:39:38 org.apache.catalina.startup.ContextConfig start
严重:Marking this application unavailable due to previous error(s)
2009-9-24 17:39:38 org.apache.catalina.core.StandardContext start
严重:Error getConfigured
2009-9-24 17:39:38 org.apache.catalina.core.StandardContext start
严重:Context [/store] startup failed due to previous errors

java.lang
类 IllegalArgumentException
java.lang.Object
java.lang.Throwable
java.lang.Exception
java.lang.RuntimeException
java.lang.IllegalArgumentException
所有已实现的接口：
Serializable
直接已知子类：
IllegalCharsetNameException,IllegalFormatException,IllegalSelectorException,IllegalThreadStateException,InvalidKeyException,InvalidOpenTypeException,InvalidParameterException,KeyAlreadyExistsException,NumberFormatException,PatternSyntaxException,UnresolvedAddressException,UnsupportedAddressTypeException,UnsupportedCharsetException
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public class IllegalArgumentExceptionextends RuntimeException抛出的异 常表明向方法传递了一个不合法或不正确的参数.
从以下版本开始：
JDK1.0
另请参见：
Thread.setPriority(int),序列化表格
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构造方法摘要
IllegalArgumentException()
构造不带详细消息的 IllegalArgumentException.
IllegalArgumentException(String s)
构造带指定详细消息的 IllegalArgumentException.
IllegalArgumentException(String message,Throwable cause)
根据指定的详细消息和原因构造一个新异常.
IllegalArgumentException(Throwable cause)
根据指定的原因和 (cause==null null :cause.toString()) 的详细消息构造一个新异常（它通常包含 cause 的类和详细消息）.
方法摘要
从类 java.lang.Throwable 继承的方法
fillInStackTrace,getCause,getLocalizedMessage,getMessage,getStackTrace,initCause,printStackTrace,printStackTrace,printStackTrace,setStackTrace,toString
从类 java.lang.Object 继承的方法
clone,equals,finalize,getClass,hashCode,notify,notifyAll,wait,wait,wait
构造方法详细信息
IllegalArgumentException
public IllegalArgumentException()构造不带详细消息的 IllegalArgumentException.
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IllegalArgumentException
public IllegalArgumentException(String s)构造带指定详细消息的 IllegalArgumentException.
参数：
s - 详细消息.
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IllegalArgumentException
public IllegalArgumentException(String message,
Throwable cause)根据指定的详细消息和原因构造一个新异常.
注意,与 cause 相关的详细消息不是 自动合并到这个异常的详细消息中的.
参数：
message - 详细消息（保存此消息,以便以后通过 Throwable.getMessage() 方法获取它）.
cause - 原因（保存此原因,以便以后通过 Throwable.getCause() 方法获取它）.（允许使用 null 值,指出原因是不存在的或是未知的.）
从以下版本开始：
1.5
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IllegalArgumentException
public IllegalArgumentException(Throwable cause)根据指定的原因和 (cause==null null :cause.toString()) 的详细消息构造一个新异常（它通常包含 cause 的类和详细消息）.此构造方法对于那些与其他 throwable（例如,PrivilegedActionException）的包装器相同的异常来说是有用的.
参数：
cause - 原因（保存此原因,以便以后通过 Throwable.getCause() 方法获取它）.（允许使用 null 值,指出原因是不存在的或是未知的.）
从以下版本开始：
1.5