我在尝试运行应用程序时遇到上述错误。我确信它与我从log4j更新到log4j2有关，因为如果我没有引用我的log4j2.xml文件，那么错误就会消失。
为什么我收到此错误？
这是完整的堆栈跟踪，如果它有帮助：
2016-09-12 12:01:26,124 main WARN JMX runtime input lookup class is not available because this JRE does not support JMX. JMX lookups will not be available, continuing configuration. java.lang.ClassCastException: Cannot cast org.apache.logging.log4j.core.lookup.JmxRuntimeInputArgumentsLookup to org.apache.logging.log4j.core.lookup.StrLookup
at java.lang.Class.cast(Unknown Source)
at org.apache.logging.log4j.util.LoaderUtil.newCheckedInstanceOf(LoaderUtil.java:168)
at org.apache.logging.log4j.core.util.Loader.newCheckedInstanceOf(Loader.java:301)
at org.apache.logging.log4j.core.lookup.Interpolator.<init>(Interpolator.java:106)
at org.apache.logging.log4j.core.config.AbstractConfiguration.<init>(AbstractConfiguration.java:116)
at org.apache.logging.log4j.core.config.DefaultConfiguration.<init>(DefaultConfiguration.java:46)
at org.apache.logging.log4j.core.layout.PatternLayout$Builder.build(PatternLayout.java:492)
at org.apache.logging.log4j.core.layout.PatternLayout.createDefaultLayout(PatternLayout.java:376)
at org.apache.logging.log4j.core.appender.ConsoleAppender$Builder.<init>(ConsoleAppender.java:168)
at org.apache.logging.log4j.core.appender.ConsoleAppender.newBuilder(ConsoleAppender.java:160)
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.logging.log4j.core.config.plugins.util.PluginBuilder.createBuilder(PluginBuilder.java:152)
at org.apache.logging.log4j.core.config.plugins.util.PluginBuilder.build(PluginBuilder.java:119)
at org.apache.logging.log4j.core.config.AbstractConfiguration.createPluginObject(AbstractConfiguration.java:918)
at org.apache.logging.log4j.core.config.AbstractConfiguration.createConfiguration(AbstractConfiguration.java:858)
at org.apache.logging.log4j.core.config.AbstractConfiguration.createConfiguration(AbstractConfiguration.java:850)
at org.apache.logging.log4j.core.config.AbstractConfiguration.doConfigure(AbstractConfiguration.java:479)
at org.apache.logging.log4j.core.config.AbstractConfiguration.initialize(AbstractConfiguration.java:219)
at org.apache.logging.log4j.core.config.AbstractConfiguration.start(AbstractConfiguration.java:231)
at org.apache.logging.log4j.core.LoggerContext.setConfiguration(LoggerContext.java:496)
at org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:566)
at org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:582)
at org.apache.logging.log4j.core.LoggerContext.start(LoggerContext.java:217)
at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:152)
at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:45)
at org.apache.logging.log4j.LogManager.getContext(LogManager.java:307)
at org.apache.log4j.Logger$PrivateManager.getContext(Logger.java:59)
at org.apache.log4j.Logger.getLogger(Logger.java:37)
at org.apache.commons.logging.impl.Log4JLogger.getLogger(Log4JLogger.java:289)
at org.apache.commons.logging.impl.Log4JLogger.<init>(Log4JLogger.java:109)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at org.apache.commons.logging.impl.LogFactoryImpl.createLogFromClass(LogFactoryImpl.java:1116)
at org.apache.commons.logging.impl.LogFactoryImpl.discoverLogImplementation(LogFactoryImpl.java:914)
at org.apache.commons.logging.impl.LogFactoryImpl.newInstance(LogFactoryImpl.java:604)
at org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:336)
at org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:310)
at org.apache.commons.logging.LogFactory.getLog(LogFactory.java:685)
at org.apache.jasper.servlet.JspServlet.<clinit>(JspServlet.java:58)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at java.lang.Class.newInstance(Unknown Source)
at org.mortbay.jetty.servlet.Holder.newInstance(Holder.java:153)
at org.mortbay.jetty.servlet.ServletHolder.initServlet(ServletHolder.java:428)
at org.mortbay.jetty.servlet.ServletHolder.doStart(ServletHolder.java:263)
at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
at org.mortbay.jetty.servlet.ServletHandler.initialize(ServletHandler.java:736)
at org.mortbay.jetty.servlet.Context.startContext(Context.java:140)
at org.mortbay.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1282)
at org.mortbay.jetty.handler.ContextHandler.doStart(ContextHandler.java:518)
at org.mortbay.jetty.webapp.WebAppContext.doStart(WebAppContext.java:499)
at com.google.gwt.dev.shell.jetty.JettyLauncher$WebAppContextWithReload.doStart(JettyLauncher.java:468)
at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:130)
at org.mortbay.jetty.handler.RequestLogHandler.doStart(RequestLogHandler.java:115)
at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:130)
at org.mortbay.jetty.Server.doStart(Server.java:224)
at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
at com.google.gwt.dev.shell.jetty.JettyLauncher.start(JettyLauncher.java:672)
at com.google.gwt.dev.DevMode.doStartUpServer(DevMode.java:509)
at com.google.gwt.dev.DevModeBase.startUp(DevModeBase.java:1068)
at com.google.gwt.dev.DevModeBase.run(DevModeBase.java:811)
at com.google.gwt.dev.Dev
Mode.main（DevMode.java:311）
答案 0 :(得分：1)
这只是一个警告，而不是一个真正的错误。它并不表示存在真正的问题。
我同意在这种情况下显示堆栈跟踪是不必要和令人困惑的。我在Log4j 2 bug跟踪器上为此提出了ticket LOG4J2-1582并修复了它。
在下一版本的Log4j 2（2.7）中，将不再显示堆栈跟踪，只显示警告消息。