File I/O - Absolute Java - page 624

Checking for the End of a Binary File
All of the ObjectInputStream methods that read from a binary file will throw an
EOFException when they try to read beyond the end of a file. So, your code can test for
the end of a binary file by catching an EOFException as illustrated in Display 10.17 .
In Display 10.17, the reading is placed in an “infinite loop” through the use of true
as the Boolean expression in the while loop. The loop is not really infinite, because
when the end of the file is reached, an exception is thrown, and that ends the entire
try block and passes control to the catch block.

EOF-
Exception

EOFException
If your program is reading from a binary file using any of the methods listed in Display 10.15
for the class ObjectInputStream , and your program attempts to read beyond the end of
the file, then an EOFException is thrown. This can be used to end a loop that reads all the
data in a file.
The class EOFException is a derived class of the class IOException . So, every exception
of type EOFException is also of type IOException .

Display 10.17 Using EOFException (part 1 of 2)

1 import java.io.ObjectInputStream;
2 import java.io.FileInputStream;
3 import java.io.EOFException;
4 import java.io.IOException;
5 import java.io.FileNotFoundException;

6 public class EOFDemo
7 {
8 public static void main(String[] args)
9 {
10 try
11 {
12 ObjectInputStream inputStream =
13 new ObjectInputStream( new FileInputStream("numbers.dat"));
14 int number;
15 System.out.println("Reading numbers in numbers.dat");
16 try
17 {
18 while ( true )
19 {
20 number = inputStream.readInt( );
21 System.out.println(number);
22 }
23 }