What are Exceptions? Many "exceptional"things can happen during the running of a program,e.g.: 。User mis-.types input checked Web page not available ·File not found Array index out of bounds unchecked Method called on a null object ·Divide by zero ·Out of memory sys errors Bug in the actual language implementation Exceptions are unexpected conditions in programs. 77 What are Exceptions? Many “exceptional” things can happen during the running of a program, e.g.: • Bug in the actual language implementation • User mis-types input • Web page not available • File not found • Divide by zero • Array index out of bounds • Method called on a null object • Out of memory Exceptions are unexpected conditions in programs. checked unchecked sys errors