Input/Output and Exception Handling - Java Concepts - page 702

Now suppose that one of the methods before the last line throws an exception. Then
the call to close is never executed! Solve this problem by placing the call to close
inside a finally clause:

PrintWriter out = new PrintWriter(filename);
try
{
writeData(out);
}
finally
{
out.close();
}

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512

In a normal case, there will be no problem. When the try block is completed, the
finally clause is executed, and the writer is closed. However, if an exception
occurs, the finally clause is also executed before the exception is passed to its
handler.

Once a try block is entered, the statements in a finally clause are guaranteed
to be executed, whether or not an exception is thrown.

Use the finally clause whenever you need to do some clean up, such as closing a
file, to ensure that the clean up happens no matter how the method exits.

It is also possible to have a finally clause following one or more catch clauses.
Then the code in the finally clause is executed whenever the try block is exited
in any of three ways:

1. After completing the last statement of the try block

2. After completing the last statement of a catch clause, if this try block

caught an exception

3. When an exception was thrown in the try block and not caught

S YNTAX 11.4 finally Clause

try
{