ID-DP008:
You need to create variable number of instances of a class (Basically controll the number of instance that are created), which
pattern should you use?
The answer is Singleton. In my view, the Singleton Pattern is a pattern that insures there is "one and only one instance" of a class, and that it is possible to provide global access to that one instance.
ID-AP006
When would you use tunneling?
The answer is A. When you do not have access to any spare ports of the firewall and need to tunnel your application through an existing port.
I am uncertain the question is about tunneling or HTTP tunneling. I think that answer D. When you are using IIOP with RMI, we need HTTP tunneling to go through firewalls.