Exception Handling - Absolute Java - page 558

Display 9.10 Use of a throws Clause (part 2 of 2)

34 public static void secondChance()
35 {
36 Scanner keyboard = new Scanner(System.in);
37
38 try
39 {
40 System.out.println("Enter numerator:");
41 int numerator = keyboard.nextInt();
42 System.out.println("Enter denominator:");
43 int denominator = keyboard.nextInt();

44 double quotient = safeDivide(numerator, denominator);
45 System.out.println(numerator + "/"
46 + denominator
47 + " = " + quotient);
48 }
49 catch (DivisionByZeroException e)
50 {
51 System.out.println("I cannot do division by zero.");
52 System.out.println("Aborting program.");
53 System.exit(0);
54 }
55 }
56 }

The input/output dialogues are
identical to those for the program in
Display 9.5.

Declaring Exceptions in a throws Clause
If a method does not catch an exception, then (in most cases) it must at least warn
programmers that any invocation of the method might possibly throw an exception.
This warning is called a throws clause , and including an exception class in a throws
clause is called declaring the exception . For example, a method that might possibly
throw a DivisionByZeroException and that does not catch the exception would
have a heading similar to the following:

throws clause

declaring an
exception

public void sampleMethod() throws DivisionByZeroException
The part throws DivisionByZeroException is a throws clause stating that an
invocation of the method sampleMethod might throw a DivisionByZeroException .
If there is more than one possible exception that can be thrown in the method definition,
then the exception types are separated by commas, as illustrated in what follows:

throws clause

public void sampleMethod()
throws DivisionByZeroException, SomeOtherException