netbeans莫明其妙的報錯

netbeans裡莫名奇妙的報錯：Illegal access: this web application instance has been stopped already.  Could not load java.lang.Object。

經過多次試驗後，發現，在項目裡新增了一個log4j.properties檔案，直接運作項目就報這個錯。如果停了tomcat後再運作項目，就沒有問題了，netbeans真是奇怪。

資訊: Illegal access: this web application instance has been stopped already.  Could not load java.lang.Object.  The eventual following stack trace is caused by an error thrown for debugging purposes as well as to attempt to terminate the thread which caused the illegal access, and has no functional impact.

java.lang.IllegalStateException

        at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1246)

        at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1206)

        at com.sun.faces.application.ConverterPropertyEditorFactory$DisposableClassLoader.loadClass(ConverterPropertyEditorFactory.java:447)

        at java.lang.ClassLoader.loadClass(ClassLoader.java:251)

        at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)

        at java.lang.Class.getDeclaredConstructors0(Native Method)

        at java.lang.Class.privateGetDeclaredConstructors(Class.java:2389)

        at java.lang.Class.getConstructor0(Class.java:2699)

        at java.lang.Class.newInstance0(Class.java:326)

        at java.lang.Class.newInstance(Class.java:308)

        at java.beans.PropertyEditorManager.findEditor(PropertyEditorManager.java:79)

        at com.sun.faces.application.ApplicationImpl.addPropertyEditorIfNecessary(ApplicationImpl.java:690)

        at com.sun.faces.application.ApplicationImpl.addConverter(ApplicationImpl.java:660)

        at com.sun.faces.config.ConfigureListener.configure(ConfigureListener.java:727)

        at com.sun.faces.config.ConfigureListener.configure(ConfigureListener.java:489)

        at com.sun.faces.config.ConfigureListener.contextInitialized(ConfigureListener.java:381)

        at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:3843)

        at org.apache.catalina.core.StandardContext.start(StandardContext.java:4350)

        at org.apache.catalina.core.StandardContext.reload(StandardContext.java:3099)

        at org.apache.catalina.manager.ManagerServlet.reload(ManagerServlet.java:913)

        at org.apache.catalina.manager.ManagerServlet.doGet(ManagerServlet.java:359)

        at javax.servlet.http.HttpServlet.service(HttpServlet.java:690)

        at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)

        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)

        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)

        at org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:196)

        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)

        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)

        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)

        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)

        at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:525)

        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)

        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)

        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)

        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286)

        at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)

        at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)

        at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)

        at java.lang.Thread.run(Thread.java:619)