interface is only blue print of class.
no implementation is made in the interface level.
abstract class is class that cannot be instantiated.

the operating system and compiler will take care of
the prioriting of the thread. So, do not worry about
it. Mostly, thread initated in the same order is
called

servlet is full program enable to running the program
through internet explorer and web server.
whereas in JSP, it is the characteristics of the JSP
JSP is shortened way of calling the function.