Exceptions - Beginning Java - page 358

}
TryBlockTest.java
Because the read() method for the object in (this object represents the standard input stream and com-
plements the out object, which is the standard output stream) can throw an I/O exception, it must be
called in a try block and have an associated catch block, unless you choose to add a throws clause to
the header line of main() .
If you run the example, it produces the following output:
First try block in main() entered
First try block in divide() entered
Code at end of first try block in divide()
finally block in divide()
result = 2
First try block in divide() entered
Arithmetic exception caught in divide()
index = 0 Expression: array[0]/array[1] is 10/0
finally block in divide()
Executing code after try block in divide()
result = 2
First try block in divide() entered
Index-out-of-bounds exception caught in divide()
array length = 3 index = 1
finally block in divide()
Executing code after try block in divide()
Index-out-of-bounds exception caught in main()
Outside first try block in main()
Press Enter to exit
In second try block in main()
finally block for second try block in main()
How It Works
All the try , catch , and finally blocks in the example have output statements so you can trace the se-
quence of execution. Note that the finally block is executed, whatever happens in the divide() meth-
od, even when the normal return is executed in the try block in divide() .
Within the divide() method, the code in the try block can throw an ArithmeticException if the ele-
ment array[index+1] of the array passed to it is 0. It can also throw an ArrayIndexOutOfBoundsEx-
ception in the try block if the index value passed to it is negative, or it results in index+2 being beyond
the array limits. Both these exceptions are caught by one or other of the catch blocks, so they are not
apparent in the calling method main() .
Note, however, that the last statement in divide() can also throw an ArrayIndexOutOfBoundsExcep-
tion :