Bug 1309174

Dennis noted you can force the problem to occur:

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I've been able to reproduce the error locally with a simple example class.

    package example;

    import javax.sql.XAConnection;
    import javax.transaction.xa.XAResource;
    import java.sql.Connection;
    import javax.sql.ConnectionEventListener;
    import javax.sql.StatementEventListener;

    public class Test implements XAConnection
    {
       public XAResource getXAResource() { return null; }

        public void addConnectionEventListener( ConnectionEventListener listener ) {}
        public void addStatementEventListener ( StatementEventListener listener ) {}
        public void close () {}
        public Connection getConnection () { return null; }
        public void removeConnectionEventListener ( ConnectionEventListener listener ){}
        public void removeStatementEventListener ( StatementEventListener listener ) {}
    }

Packaged in a module, with the recommended dependencies for the Oracle driver:

        <module name="javax.api"/>
        <module name="javax.transaction.api"/>

If the following three lines are run, in any order, an error occurs in the 3rd one:

    Class.forName ( "javax.transaction.xa.XAResource", true, example.Test.class.getClassLoader() );
    Class.forName ( "javax.transaction.xa.XAResource", true, javax.sql.XAConnection.class.getClassLoader() );
    new example.Test();

If example.Test is last, the error is:

    ERROR [org.apache.catalina.core.ContainerBase.[jboss.web].[default-host].[/test].[jsp]] (http-/127.0.0.1:8080-1) JBWEB000236: Servlet.service() for servlet jsp threw exception: java.lang.LinkageError: loader constraint violation in interface itable initialization: when resolving method "example.Test.getXAResource()Ljavax/transaction/xa/XAResource;" the class loader (instance of org/jboss/modules/ModuleClassLoader) of the current class, example/Test, and the class loader (instance of <bootloader>) for interface javax/sql/XAConnection have different Class objects for the type tion/xa/XAResource; used in the signature

If one of the Class.forNames is last, the error is (with a different classloader for each):

    ERROR [org.apache.catalina.core.ContainerBase.[jboss.web].[default-host].[/test].[jsp]] (http-/127.0.0.1:8080-1) JBWEB000236: Servlet.service() for servlet jsp threw exception: java.lang.LinkageError: loader constraint violation: loader (instance of org/jboss/modules/ModuleClassLoader) previously initiated loading for a different type with name "javax/transaction/xa/XAResource"
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A customer experienced this through what appears to be regular usage of a connection, there is likely to be some kind of race where it works unless a variety of classes are loaded in exactly the right order.

Created attachment 1142722 [details]
bz1309174-test.zip

Attached test case.  See included README for details on running it.

Verified with EAP 6.4.8.CP.CR2

Jiri Pallich <jpallich> updated the status of jira JBEAP-3340 to Closed

Retroactively bulk-closing issues from released EAP 6.4 cumulative patches.