我有一个使用 JSF 2.0 (impl Mojarra 2.1.6) 的 EE 应用程序。我使用的服务器是 glassfish 3.1.2，CDI 实现是 WELD。有时，当我运行应用程序时，会出现以下异常：
org.jboss.weld.exceptions.DefinitionException: WELD-000047 Specializing bean must extend another bean: Managed Bean [class org.apache.myfaces.extensions.cdi.jsf2.impl.Jsf2ModuleStartupObserver] with qualifiers [@Any @Default]
at org.jboss.weld.bean.ManagedBean.specialize(ManagedBean.java:458)
at org.jboss.weld.bean.AbstractBean.initialize(AbstractBean.java:121)
at org.jboss.weld.bean.AbstractClassBean.initialize(AbstractClassBean.java:190)
at org.jboss.weld.bean.ManagedBean.initialize(ManagedBean.java:322)
at org.jboss.weld.bootstrap.AbstractBeanDeployer.deploy(AbstractBeanDeployer.java:115)
at org.jboss.weld.bootstrap.BeanDeployment.deployBeans(BeanDeployment.java:204)
at org.jboss.weld.bootstrap.WeldBootstrap.deployBeans(WeldBootstrap.java:344)
at org.glassfish.weld.WeldDeployer.event(WeldDeployer.java:179)
at org.glassfish.kernel.event.EventsImpl.send(EventsImpl.java:128)
at org.glassfish.internal.data.ApplicationInfo.load(ApplicationInfo.java:277)
at com.sun.enterprise.v3.server.ApplicationLifecycle.deploy(ApplicationLifecycle.java:460)
at com.sun.enterprise.v3.server.ApplicationLifecycle.deploy(ApplicationLifecycle.java:240)
at org.glassfish.deployment.admin.DeployCommand.execute(DeployCommand.java:389)
at com.sun.enterprise.v3.admin.CommandRunnerImpl$1.execute(CommandRunnerImpl.java:348)
at com.sun.enterprise.v3.admin.CommandRunnerImpl.doCommand(CommandRunnerImpl.java:363)
at com.sun.enterprise.v3.admin.CommandRunnerImpl.doCommand(CommandRunnerImpl.java:1085)
at com.sun.enterprise.v3.admin.CommandRunnerImpl.access$1200(CommandRunnerImpl.java:95)
at com.sun.enterprise.v3.admin.CommandRunnerImpl$ExecutionContext.execute(CommandRunnerImpl.java:1291)
at com.sun.enterprise.v3.admin.CommandRunnerImpl$ExecutionContext.execute(CommandRunnerImpl.java:1259)
at com.sun.enterprise.v3.admin.AdminAdapter.doCommand(AdminAdapter.java:461)
at com.sun.enterprise.v3.admin.AdminAdapter.service(AdminAdapter.java:212)
at com.sun.grizzly.tcp.http11.GrizzlyAdapter.service(GrizzlyAdapter.java:179)
at com.sun.enterprise.v3.server.HK2Dispatcher.dispath(HK2Dispatcher.java:117)
at com.sun.enterprise.v3.services.impl.ContainerMapper$Hk2DispatcherCallable.call(ContainerMapper.java:354)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:195)
at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:849)
at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:746)
at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1045)
at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:228)
at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
at java.lang.Thread.run(Thread.java:680)
它并不总是发生；当它发生时，如果我再次运行该应用程序，它就可以正常工作。但这很烦人，我想知道为什么会这样。有人知道吗？