Connection name xyz is not defined

some times the error comes as:

The description of the error in log appears something like:

<LifecycleImpl> <_handleException> ADF_FACES-60098:Faces lifecycle receives unhandled exceptions in phase RENDER_RESPONSE 6
oracle.jbo.JboException: JBO-29000: Unexpected exception caught: oracle.jbo.ConfigException, msg=JBO-33003: Connection name 11g is not defined.
    at oracle.jbo.common.ampool.PoolMgr.findPool(PoolMgr.java:529)
    at oracle.adf.model.bc4j.DCJboDataControl.findApplicationPool(DCJboDataControl.java:565)
    at oracle.adf.model.bc4j.DCJboDataControl.initializeSessionCookie(DCJboDataControl.java:389)
    at oracle.adf.model.bc4j.DCJboDataControl.initializeJboSession(DCJboDataControl.java:303)
    at oracle.adf.model.bc4j.DataControlFactoryImpl.createSessionInternal(DataControlFactoryImpl.java:199)
    at oracle.adf.model.bc4j.DataControlFactoryImpl.createSession(DataControlFactoryImpl.java:123)
    at oracle.adf.model.binding.DCDataControlReference.getDataControl(DCDataControlReference.java:167)
    at oracle.adf.model.BindingContext.instantiateDataControl(BindingContext.java:1024)

This error generally comes while migrating the code from one environment to the other.
especially when you have changed the database connection and then trying to deploy.
I have produced this error by developing the code with database connection name "11g" and then changing the database connection and giving some other connection name say "abc".

To solve this issue right click on Application Module and go to configuration...

here you can see that though we have changed the database connection from "11g" to "abc", but here it is still showing 11g details.

click on the Edit button and then press OK.
you will notice that now the connection details has been changed to "abc" which is the desired one.

Now run your Application.
It should give the desired output. :)