HANDLING EXCEPTIONS AND EVENTS - Java Programming: From Problem Analysis to Program Design - page 737

TABLE 11-2 class Exception and its Constructors

public Exception()
//Default constructor
//Creates a new instance of the class Exception

public Exception(String str)
//Constructor with parameters
//Creates a new instance of the class Exception. The parameter
//str specifies the message string.

Because the class Exception is a subclass of the class Throwable , the class
Exception and its subclasses inherit the methods getMessage , printStackTrace ,
and toString . The method getMessage returns the string containing the detailed
message stored in the exception object. The method toString returns the detailed
message stored in the exception object as well as the name of the exception class. The
method printStackTrace is discussed later in this chapter.
The class RuntimeException is the superclass of the classes designed to deal with excep-
tions, such as division by zero, array index out of bounds, and number format (see Figure 11-2).
Table 11-3 lists some of the exception classes and the type of exceptions they throw.

TABLE 11-3 Some of Java's Exception Classes

Exception Class Description

Arithmetic errors such as division by
zero

ArithmeticException

1
1

Array index is either less than 0 or
greater than or equal to the length of
the array.

ArrayIndexOutOfBoundsException

Reference to a file that cannot be
found

FileNotFoundException

Calling a method with illegal
arguments

IllegalArgumentException

An array or a string index is out of
bounds.

IndexOutOfBoundsException

Reference to an object that has not
been instantiated

NullPointerException