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From: Knute Johnson <september@knutejohnson.com>
Newsgroups: comp.lang.java.programmer
Subject: Re: Trying to Understand Purpose of a Catch Block for IOException in the Presence of One for FileNotFound
Date: Fri, 12 Aug 2011 08:54:44 -0700
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On 8/12/2011 8:39 AM, KevinSimonson wrote:
> If I write a piece of code that constructs an object of class
> <PrintWriter>  by passing it an object of class<BufferedWriter>,
> constructed by passing _it_ an object of type<FileWriter>  (all three
> classes under<java.io>), don't have a<throws>  clause, have only a
> <catch>  clause for<FileNotFoundException>, and then try to compile
> the code the compiler complains, telling me, "unreported exception
> java.io.IOException java.io.IOException: must be caught or declared to
> be thrown".  Of course, if I put a<catch>  clause there for
> <IOException>, that fixes the problem and the program compiles just
> fine.
>
> If, on the other hand, I write a piece of code that constructs an
> object of class<Scanner>, constructed by passing it an object of type
> <File>, don't have a<throws>  clause for<FileNotFoundException>, and
> don't put the constructor call in a<try>  block at all, I get a
> similar complaint about me not saying anything about exception
> <FileNotFound>.
>
> Finally, if I have some code that has constructors for _both
> <PrintWriter>  and_<Scanner>, I have to have a<catch>  clause for
> _both<IOException>  and_<FileNotFoundException>, in order to keep the
> compiler happy.  But in such a situation I have not been able to find
> a way to _actually get<IOException>  thrown_!  What is the purpose of
> having a<catch>  block for<IOException>  if nothing I do with my code
> will actually throw an<IOException>  that is not a
> <FileNotFoundException>?  Or, alternately, is there something I can do
> to _get_ an<IOException>  that is not a<FileNotFoundException>
> thrown?
>
> I would appreciate any information anyone can give me on this.
>
> Kevin Simonson

Show us the actual code.

-- 

Knute Johnson