int a = args.length;
System.out.println("a = " + a);
int b = 42 / a;
int c[] = { 1 };
c[42] = 99;
} catch(ArithmeticException e) {
System.out.println("Divide by 0: " + e);
} catch(ArrayIndexOutOfBoundsException e) {
System.out.println("Array index oob: " + e);
}
System.out.println("After try/catch blocks.");
}
}
This program will cause a division-by-zero exception if it is started with no command-
line arguments, since a will equal zero. It will survive the division if you provide a
command-line argument, setting a to something larger than zero. But it will cause an
ArrayIndexOutOfBoundsException, since the int array c has a length of 1, yet the program
attempts to assign a value to c[42].
Here is the output generated by running it both ways:
C:\>java MultiCatch
a=0
Divide by 0: java.lang.ArithmeticException: / by zero
After try/catch blocks.
C:\>java MultiCatch TestArg
a=1
Array index oob: java.lang.ArrayIndexOutOfBoundsException:42
After try/catch blocks.
When you use multiple catch statements, it is important to remember that exception
subclasses must come before any of their superclasses. This is because a catch statement
that uses a superclass will catch exceptions of that type plus any of its subclasses. Thus, a
subclass would never be reached if it came after its superclass. Further, in Java, unreachable
code is an error. For example, consider the following program:
/* This program contains an error.
A subclass must come before its superclass in
a series of catch statements. If not,
unreachable code will be created and a
compile-time error will result.
*/
class SuperSubCatch {
public static void main(String args[]) {
try {
int a = 0;
int b = 42 / a;
} catch(Exception e) {
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