A patent is supposed to have a technical effect. A patent that does not have a clear and well defined technical effect can be voided on technicality.
It is not specific to Oracle patents, it is a common disease in the industry. When you read a patent done in IT and Telecoms space , 70%+ of the cases you end up having no clue what it does. It has been drafted to be so vague and all-encompassing that the technical effect is no longer clear.
AFAIK, the current practice is moving towards the following: if the technical effect is not clear from the claims it is inferred from the description and the patent narrowed down to whatever is given as examples in the description.
Trying to invalidate patents on this count is quite rare though. Nobody wants to create a precedent that will invalidate half of the IPR out there including their own.