What is the idea behind Render Response and Exception Handling in TF?

Question

Dear All,
While searching for answer for my question, I find it hard to decipher this line.
task flow exception handling doesn't handle any exception that is in Render Response phase
I found this several times in many post like this.
Re: ADF Exception handling (including RENDER RESPNSE PHASE)
and this
Re: Exception Handling in TaskFlow
What's the idea behind exception handling in task flow that is related to JSF/ADF life cycle?
I can't find a resource on why I should know what phase an exception has been thrown?
Sorry if my question might be vague/ignorant to others, but I just would like to know the idea from experts around here. :)
Thanks.
JDEV 11G PS4

Answer 1

Hi,
Render Response is the last lifecycle phase processed during JSF request. The ADF controller has no chance of handling exceptions that occur during this time (example, exception thrown in managed bean) and therefore in its default exception handling implementation ignores this lifecycle phase. As an application developer you don't need to know when an exception is raised. However, if you find that an exception occurs during Render Response and it is not handled by the ADFc declarative exception handler, then you know. You can try and override the framework exception handler as explained here:
https://blogs.oracle.com/jdevotnharvest/entry/extending_the_adf_controller_exception_handler
However, better practice is to use try/catch blocks surrounding e.g. calls in a managed bean that could cause exceptions
Frank