When bundling derby.jar into our application, we get the following error under 6.0.0.M4. It appears to be looking for a method signature that doesn't exist in the main classloader:

06:59:18,314 WARN [org.jboss.deployment.MainDeployer] Failed to deploy: file:/Users/matt/Projects/qato/deploy/qato.war/: org.jboss.deployers.client.spi.IncompleteDeploymentException: Summary of incomplete deployments (SEE PREVIOUS ERRORS FOR DETAILS):

• • • DEPLOYMENTS IN ERROR: Name -> Error

vfs:///Users/matt/Projects/qato/deploy/qato.war/ -> org.jboss.deployers.spi.DeploymentException: Error during deploy: vfs:///Users/matt/Projects/qato/deploy/qato.war/

DEPLOYMENTS IN ERROR:
Deployment "vfs:///Users/matt/Projects/qato/deploy/qato.war/" is in error due to the following reason(s): java.lang.LinkageError: loader constraint violation in interface itable initialization: when resolving method "org.apache.derby.jdbc.EmbedXAConnection.getXAResource()Ljavax/transaction/xa/XAResource;" the class loader (instance of org/jboss/classloader/spi/base/BaseClassLoader) of the current class, org/apache/derby/jdbc/EmbedXAConnection, and the class loader (instance of <bootloader>) for interface javax/sql/XAConnection have different Class objects for the type javax/transaction/xa/XAResource used in the signature

at org.jboss.deployers.plugins.deployers.DeployersImpl.checkComplete(DeployersImpl.java:1370) [:2.2.0.Alpha6]
at org.jboss.deployers.plugins.deployers.DeployersImpl.checkComplete(DeployersImpl.java:1316) [:2.2.0.Alpha6]
at org.jboss.deployers.plugins.main.MainDeployerImpl.checkComplete(MainDeployerImpl.java:968) [:2.2.0.Alpha6]
at org.jboss.deployers.plugins.main.MainDeployerImpl.checkComplete(MainDeployerImpl.java:957) [:2.2.0.Alpha6]
at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:373) [:6.0.0.20100721-M4]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [:1.6.0_20]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) [:1.6.0_20]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) [:1.6.0_20]
at java.lang.reflect.Method.invoke(Method.java:597) [:1.6.0_20]
at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:157) [:6.0.0.Beta5]
at org.jboss.mx.server.Invocation.dispatch(Invocation.java:96) [:6.0.0.Beta5]
at org.jboss.mx.server.Invocation.invoke(Invocation.java:88) [:6.0.0.Beta5]
at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:271) [:6.0.0.Beta5]
at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:670) [:6.0.0.Beta5]
at org.jboss.system.server.jmx.MBeanServerWrapper.invoke(MBeanServerWrapper.java:138) [:6.0.0.20100721-M4 (Build SVNTag:JBoss_6.0.0.20100721-M4 date: 20100723)]
at javax.management.remote.rmi.RMIConnectionImpl.doOperation(RMIConnectionImpl.java:1427) [:1.6.0_20]
at javax.management.remote.rmi.RMIConnectionImpl.access$200(RMIConnectionImpl.java:72) [:1.6.0_20]
at javax.management.remote.rmi.RMIConnectionImpl$PrivilegedOperation.run(RMIConnectionImpl.java:1265) [:1.6.0_20]
at javax.management.remote.rmi.RMIConnectionImpl.doPrivilegedOperation(RMIConnectionImpl.java:1360) [:1.6.0_20]
at javax.management.remote.rmi.RMIConnectionImpl.invoke(RMIConnectionImpl.java:788) [:1.6.0_20]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [:1.6.0_20]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) [:1.6.0_20]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) [:1.6.0_20]
at java.lang.reflect.Method.invoke(Method.java:597) [:1.6.0_20]
at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:305) [:1.6.0_20]
at sun.rmi.transport.Transport$1.run(Transport.java:159) [:1.6.0_20]
at java.security.AccessController.doPrivileged(Native Method) [:1.6.0_20]
at sun.rmi.transport.Transport.serviceCall(Transport.java:155) [:1.6.0_20]
at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:535) [:1.6.0_20]
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:790) [:1.6.0_20]
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:649) [:1.6.0_20]
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) [:1.6.0_20]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) [:1.6.0_20]
at java.lang.Thread.run(Thread.java:637) [:1.6.0_20]

or