Oracle® WebLogic managed server reaches ADMIN state during startup due to name collision

The problem

When starting a Oracle® WebLogic managed server it halts when reaching the ADMIN state. 

Looking at the managed server's out file I saw the following error:

<Mar 15, 2016 8:45:40 AM UTC> <Error> <Deployer> <BEA-149231> <Unable to set the activation state to true for the application "MyDataSource".

weblogic.application.ModuleException: weblogic.common.ResourceException: Failed to bind remote object (ClusterableRemoteRef(6058417782957188722S:my-server:soa_domain:soa_server1 null)/289        [weblogic.jdbc.common.internal.RemoteDataSource]) to replica aware stub at MY_DS(ClusterableRemoteRef(6058417782957188722S:my-server:soa_domain:soa_server1 [6058417782957188722S:my-server:soa_domain:soa_server1/288])/288        [weblogic.jdbc.common.internal.RemoteDataSource])

        at weblogic.jdbc.module.JDBCModule.activate(JDBCModule.java:411)

        at weblogic.application.internal.flow.ModuleListenerInvoker.activate(ModuleListenerInvoker.java:114)

        at weblogic.application.internal.flow.ModuleStateDriver$2.next(ModuleStateDriver.java:195)

        at weblogic.application.internal.flow.ModuleStateDriver$2.next(ModuleStateDriver.java:190)

        at weblogic.application.utils.StateMachineDriver.nextState(StateMachineDriver.java:42)

        Truncated. see log file for complete stacktrace

Caused By: weblogic.common.ResourceException: Failed to bind remote object (ClusterableRemoteRef(6058417782957188722S:my-server:soa_domain:soa_server1 null)/289   [weblogic.jdbc.common.internal.RemoteDataSource]) to replica aware stub at MY_DS(ClusterableRemoteRef(6058417782957188722S:my-server:

The cause

The error above says I have a problem starting the MyDataSource data source due to a name collision. Logging into the WebLogic console, and looking at my data sources, I realized I had two data sources with the same JNDI location. The reason was that I had prepared a new data source long time ago, and forgotten all about it. During the startup of the managed server, my new data source had started up, but the old one could of course not start since it had the same JNDI  location.

The solution

1. Removed the old and obsolete data source with the conflicting JNDI location.
2. Checked the managed server's out file for other errors, and there were none. 
3. Resumed startup of the managed server so the server state changed from ADMIN to RUNNING.