@Rajiv It think we need to be consistent in the specification. If we say that AsyncContext objects throw ISE if used after the request lifecycle is complete, then I think we also need to do the same for the request and response instances themselves. I think it is too confusing to have some objects be reusable and others not.
Besides if AsyncContext.getRequest() throws an ISE, but Request itself is not usable after the completion of the request life cycle, then we have a race condition as an async thread might call getRequest() a nano second before the end of the request life cycle and then perform illegal operations on the request object it got in return.
So either we have to explicitly prohibit all recycling of objects and say that request/response/contexts are all invalid after the completion; OR we continue as we are saying that it is the applications responsibility to not call methods on any of these objects after the lifecycle has completed.
I do not think a half way house of some objects being recyclable while other are not is viable nor easy to understand.
If this was a green field spec, I think that requiring fresh objects on every cycle would be best. But as we have lots of existing code, then I now favour the status quo and that we continue to allow recycling of these objects.