Sometimes we would like to customize the error messages displayed to the end user in Oracle ADF. We can do this by creating the custom DCErrorHandlerImpl Class and configuring it as the ErrorHnadler class in DataBindings.cpx
More details in the below blog
http://jneelmani.blogspot.com/2013/10/adf-11g-how-to-customize-default-adf-bc.html
More details in the below blog
http://jneelmani.blogspot.com/2013/10/adf-11g-how-to-customize-default-adf-bc.html