java.lang.LinkageErrors seen during start of JBoss AS 5.1 with admin-console.war deployed

During the inialization of the administration console, the rhq-platform-plugin gets loaded, searches jaxb.properties for a JAXB implementation and finds jaxb-impl.jar from $JBOSS_HOME/lib

2009-02-20 15:20:41,594 INFO [org.jboss.on.embedded.BootstrapAction] (main) Bootstrapping Administration Console v1.1.1-SNAPSHOT...
2009-02-20 15:20:41,594 DEBUG [org.jboss.on.embedded.BootstrapAction] (main) Reconfiguring JDK logging...
2009-02-20 15:20:41,617 DEBUG [org.jboss.on.embedded.BootstrapAction] (main) Configuring Mock Scenario Loader...
2009-02-20 15:20:41,618 INFO [org.rhq.core.pc.PluginContainer] (main) Initializing Plugin Container v1.2.0-SNAPSHOT...
2009-02-20 15:20:41,723 DEBUG [org.rhq.core.pc.PluginContainer] (main) Starting and configuring container service: PluginManager
2009-02-20 15:20:41,737 DEBUG [org.rhq.core.pc.plugin.PluginManager] (main) Plugin found at: jndi:/localhost/admin-console/plugins/rhq-platform-plugin-1.2.0-SNAPSHOT.jar
2009-02-20 15:20:41,741 DEBUG [org.rhq.core.clientapi.descriptor.AgentPluginDescriptorUtil] (main) Loading plugin descriptor from plugin jar at [jndi:/localhost/admin-console/plugins/rhq-platform-plugin-1.2.0-SNAPSHOT.jar]...
2009-02-20 15:20:41,741 FINE [javax.xml.bind] (main) Searching jaxb.properties
2009-02-20 15:20:41,742 FINE [javax.xml.bind] (main) Searching the system property
2009-02-20 15:20:41,742 FINE [javax.xml.bind] (main) Searching META-INF/services
2009-02-20 15:20:41,743 FINE [javax.xml.bind] (main) Trying to load com.sun.xml.bind.v2.ContextFactory
2009-02-20 15:20:41,744 FINE [javax.xml.bind] (main) loaded com.sun.xml.bind.v2.ContextFactory from vfszip:/home/smcgowan2/workspace/Branch_5_x/build/output/jboss-5.1.0.Beta1/lib/jaxb-impl.jar/com/sun/xml/bind/v2/ContextFactory.class
2009-02-20 15:20:41,748 FINE [com.sun.xml.bind.v2.ContextFactory] (main) Property com.sun.xml.bind.XmlAccessorFactoryis not active. Using JAXB's implementation
2009-02-20 15:20:41,947 FINE [com.sun.xml.bind.v2.runtime.reflect.opt.OptimizedAccessorFactory] (main) Using optimized Accessor for protected org.rhq.core.clientapi.descriptor.plugin.Version org.rhq.core.clientapi.descriptor.plugin.ResourceDescriptor.version

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Next, while loading jopr-jboss-as-5-plugin, the same seach occurs but this time loading the class results in an exception:

2009-02-20 15:20:44,006 DEBUG [org.rhq.core.pc.plugin.PluginManager] (main) Loading independent plugin [JBossAS5] from URL: jndi:/localhost/admin-console/plugins/jopr-jboss-as-5-plugin-2.2.0-SNAPSHOT.jar
2009-02-20 15:20:44,006 DEBUG [org.rhq.core.pc.plugin.PluginManager] (main) Loading plugin from: jndi:/localhost/admin-console/plugins/jopr-jboss-as-5-plugin-2.2.0-SNAPSHOT.jar
2009-02-20 15:20:44,026 DEBUG [org.rhq.core.pc.plugin.PluginDescriptorLoader] (main) Created classloader for plugin [jndi:/localhost/admin-console/plugins/jopr-jboss-as-5-plugin-2.2.0-SNAPSHOT.jar]
2009-02-20 15:20:44,026 DEBUG [org.rhq.core.clientapi.descriptor.AgentPluginDescriptorUtil] (main) Loading plugin descriptor from plugin jar at [jndi:/localhost/admin-console/plugins/jopr-jboss-as-5-plugin-2.2.0-SNAPSHOT.jar]...
2009-02-20 15:20:44,026 FINE [javax.xml.bind] (main) Searching jaxb.properties
2009-02-20 15:20:44,027 FINE [javax.xml.bind] (main) Searching the system property
2009-02-20 15:20:44,027 FINE [javax.xml.bind] (main) Searching META-INF/services
2009-02-20 15:20:44,027 FINE [javax.xml.bind] (main) Trying to load com.sun.xml.bind.v2.ContextFactory
2009-02-20 15:20:44,028 FINE [javax.xml.bind] (main) loaded com.sun.xml.bind.v2.ContextFactory from vfszip:/home/smcgowan2/workspace/Branch_5_x/build/output/jboss-5.1.0.Beta1/lib/jaxb-impl.jar/com/sun/xml/bind/v2/ContextFactory.class
2009-02-20 15:20:44,029 FINE [com.sun.xml.bind.v2.ContextFactory] (main) Property com.sun.xml.bind.XmlAccessorFactoryis not active. Using JAXB's implementation
2009-02-20 15:20:44,308 FINE [com.sun.xml.bind.v2.runtime.reflect.opt.Injector] (main) Unable to inject org/rhq/core/clientapi/descriptor/plugin/ResourceDescriptor$JaxbAccessorF_version
java.lang.reflect.InvocationTargetException
at sun.reflect.GeneratedMethodAccessor252.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at com.sun.xml.bind.v2.runtime.reflect.opt.Injector.inject(Injector.java:181)
at com.sun.xml.bind.v2.runtime.reflect.opt.Injector.inject(Injector.java:85)
at com.sun.xml.bind.v2.runtime.reflect.opt.AccessorInjector.prepare(AccessorInjector.java:87)
at com.sun.xml.bind.v2.runtime.reflect.opt.OptimizedAccessorFactory.get(OptimizedAccessorFactory.java:165)
at com.sun.xml.bind.v2.runtime.reflect.Accessor$FieldReflection.optimize(Accessor.java:253)
at com.sun.xml.bind.v2.runtime.property.SingleElementNodeProperty.<init>(SingleElementNodeProperty.java:89)
at sun.reflect.GeneratedConstructorAccessor47.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:494)
at com.sun.xml.bind.v2.runtime.property.PropertyFactory.create(PropertyFactory.java:124)

Caused by: java.lang.LinkageError: duplicate class definition: org/rhq/core/clientapi/descriptor/plugin/ResourceDescriptor$JaxbAccessorF_version
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:620)
at java.lang.ClassLoader.defineClass(ClassLoader.java:465)

The server does start.