CHAPTER 100 — Exceptions

A program often encounters problems as it executes. It may have trouble reading data, there might be illegal characters in the data, or an array index might go out of bounds. The Java Exception class enables you to deal with such problems.

Input and output are especially error prone. Exception handling is essential for I/O programming, the topic of several chapters following.

Chapter Topics:

Exceptions and Errors
Runtime Exceptions
Arithmetic Exceptions
try, catch, and finally statements
User-friendly programs

QUESTION 1:

Inspect the following. What went wrong?

C:\JavaSource>java  Square 
Enter an integer: rats
Exception in thread "main" java.util.InputMismatchException
        at java.util.Scanner.throwFor(Unknown Source)
        at java.util.Scanner.next(Unknown Source)
        at java.util.Scanner.nextInt(Unknown Source)
        at java.util.Scanner.nextInt(Unknown Source)
        at Square.main(Square.java:12)