There is a good article by Frank Nimphius explaining how to create custom exception handler for ADF application .Frank's blog
But I noticed that it is missing an important details. It is common when someone that KNOWS takes things as obvious and just don’t mention something important.
In this case I am talking about this step
Create a textfile with the name “oracle.adf.view.rich.context.ExceptionHandler” (without the quotes) and store it in .adf\META-INF\services (you need to create the “services” folder)
I opened my project and did exactly as instructed. Created the folder and placed the file. And…. nothing happened
Eventually after digging another 20 minutes in Google I eventually found that the actual place I need to put the file is .adf\META-INF directory which is located in the main application directory
Details… pay attention to details.