The DNS is the server which creats a mapping between the names of machines and their IP numbers.
More than one IP numbers can belong to one name. This can mean that also several machines belong to that name. This would be usefull if this address is often requested.
It is impossible to build up a connection to a machine protected by a firewall.
A hostile applet is an applet which provides an attack against a user's system.
An applet is an executable Java program embedded in a Webpage.
The applet pool is a special array of an applet.
Classes are compiled Javacode. Applets can load classes from the so called Classpath.