Timber,
This really has nothing to do with
servlets, per se. When you extend a class and override a method,
Java insists that the new method cannot be declared as throwing checked exceptions of classes other than those that were declared by the original method. However, It may throw exceptions derived from the base-class exceptions, some of the base-class exceptions, or none of them at all.
-BK
Barry Kushnir, SCJP, SCWCD, SCEA