Linkage error

I got the following error after redeploying this morning :

java.lang.RuntimeException: Could not create Component: ClassName
 at org.jboss.seam.init.Initialization.addComponent(Initialization.java:1178)
 at org.jboss.seam.init.Initialization.installComponents(Initialization.java:1094)
 at org.jboss.seam.init.Initialization.init(Initialization.java:728)
 at org.jboss.seam.servlet.SeamListener.contextInitialized(SeamListener.java:35)
 at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:3856)
 at org.apache.catalina.core.StandardContext.start(StandardContext.java:4361)
 at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:790)
 at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:770)
 at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:553)
 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:585)
 at org.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:296)
 at org.jboss.mx.server.RawDynamicInvoker.invoke(RawDynamicInvoker.java:164)
 at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659)
 at org.apache.catalina.core.StandardContext.init(StandardContext.java:5312)
 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:585)
 at org.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:296)
 at org.jboss.mx.server.RawDynamicInvoker.invoke(RawDynamicInvoker.java:164)
 at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659)
 at org.jboss.web.tomcat.service.TomcatDeployer.performDeployInternal(TomcatDeployer.java:301)
 at org.jboss.web.tomcat.service.TomcatDeployer.performDeploy(TomcatDeployer.java:104)
 at org.jboss.web.AbstractWebDeployer.start(AbstractWebDeployer.java:375)
 at org.jboss.web.WebModule.startModule(WebModule.java:83)
 at org.jboss.web.WebModule.startService(WebModule.java:61)
 at org.jboss.system.ServiceMBeanSupport.jbossInternalStart(ServiceMBeanSupport.java:289)
 at org.jboss.system.ServiceMBeanSupport.jbossInternalLifecycle(ServiceMBeanSupport.java:245)
 at sun.reflect.GeneratedMethodAccessor3.invoke(Unknown Source)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
 at java.lang.reflect.Method.invoke(Method.java:585)
 at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155)
 at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94)
 at org.jboss.mx.server.Invocation.invoke(Invocation.java:86)
 at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264)
 at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659)
 at org.jboss.system.ServiceController$ServiceProxy.invoke(ServiceController.java:978)
 at $Proxy0.start(Unknown Source)
 at org.jboss.system.ServiceController.start(ServiceController.java:417)
 at sun.reflect.GeneratedMethodAccessor9.invoke(Unknown Source)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
 at java.lang.reflect.Method.invoke(Method.java:585)
 at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155)
 at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94)
 at org.jboss.mx.server.Invocation.invoke(Invocation.java:86)
 at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264)
 at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659)
 at org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:210)
 at $Proxy44.start(Unknown Source)
 at org.jboss.web.AbstractWebContainer.start(AbstractWebContainer.java:466)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
 at java.lang.reflect.Method.invoke(Method.java:585)
 at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155)
 at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94)
 at org.jboss.mx.interceptor.AbstractInterceptor.invoke(AbstractInterceptor.java:133)
 at org.jboss.mx.server.Invocation.invoke(Invocation.java:88)
 at org.jboss.mx.interceptor.ModelMBeanOperationInterceptor.invoke(ModelMBeanOperationInterceptor.java:142)
 at org.jboss.mx.interceptor.DynamicInterceptor.invoke(DynamicInterceptor.java:97)
 at org.jboss.system.InterceptorServiceMBeanSupport.invokeNext(InterceptorServiceMBeanSupport.java:238)
 at org.jboss.wsf.container.jboss42.DeployerInterceptor.start(DeployerInterceptor.java:87)
 at org.jboss.deployment.SubDeployerInterceptorSupport$XMBeanInterceptor.start(SubDeployerInterceptorSupport.java:188)
 at org.jboss.deployment.SubDeployerInterceptor.invoke(SubDeployerInterceptor.java:95)
 at org.jboss.mx.server.Invocation.invoke(Invocation.java:88)
 at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264)
 at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659)
 at org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:210)
 at $Proxy45.start(Unknown Source)
 at org.jboss.deployment.MainDeployer.start(MainDeployer.java:1025)
 at org.jboss.deployment.MainDeployer.start(MainDeployer.java:1015)
 at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:819)
 at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:782)
 at sun.reflect.GeneratedMethodAccessor24.invoke(Unknown Source)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
 at java.lang.reflect.Method.invoke(Method.java:585)
 at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155)
 at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94)
 at org.jboss.mx.interceptor.AbstractInterceptor.invoke(AbstractInterceptor.java:133)
 at org.jboss.mx.server.Invocation.invoke(Invocation.java:88)
 at org.jboss.mx.interceptor.ModelMBeanOperationInterceptor.invoke(ModelMBeanOperationInterceptor.java:142)
 at org.jboss.mx.server.Invocation.invoke(Invocation.java:88)
 at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264)
 at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659)
 at org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:210)
 at $Proxy9.deploy(Unknown Source)
 at org.jboss.deployment.scanner.URLDeploymentScanner.deploy(URLDeploymentScanner.java:421)
 at org.jboss.deployment.scanner.URLDeploymentScanner.scan(URLDeploymentScanner.java:610)
 at org.jboss.deployment.scanner.AbstractDeploymentScanner$ScannerThread.doScan(AbstractDeploymentScanner.java:263)
 at org.jboss.deployment.scanner.AbstractDeploymentScanner$ScannerThread.loop(AbstractDeploymentScanner.java:274)
 at org.jboss.deployment.scanner.AbstractDeploymentScanner$ScannerThread.run(AbstractDeploymentScanner.java:225)
Caused by: java.lang.LinkageError: loader constraints violated when linking fully/qualified/ClassName class
 at java.lang.Class.getDeclaredMethods0(Native Method)
 at java.lang.Class.privateGetDeclaredMethods(Class.java:2395)
 at java.lang.Class.privateGetPublicMethods(Class.java:2519)
 at java.lang.Class.getMethods(Class.java:1406)
 at org.jboss.seam.Component.hasAnnotation(Component.java:1125)
 at org.jboss.seam.Component.<init>(Component.java:219)
 at org.jboss.seam.Component.<init>(Component.java:206)
 at org.jboss.seam.init.Initialization.addComponent(Initialization.java:1162)
 ... 93 more

Of course the app was working when I showed up this morning and fired up JBoss.

This post on JBoss' wiki points out the problem. I liked this line from the wiki post, "Depending on how unlucky you may be, you might get a LinkageError or ClassCircularityError as well."

I checked the jboss-app.xml inside my ear and sure enough it was empty. I have no idea how that happened. However, the fix is simple. I just added the following :

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE jboss-app
  PUBLIC "-//JBoss//DTD J2EE Application 4.2//EN"
  "http://www.jboss.org/j2ee/dtd/jboss-app_4_2.dtd">

<jboss-app>
 <loader-repository>
    seam.jboss.org:loader=appName
 </loader-repository>
</jboss-app>