Re: Java language and library suggestions

From:

Tom Anderson <twic@urchin.earth.li>

Newsgroups:

comp.lang.java.programmer

Date:

Sun, 19 Jul 2009 23:57:17 +0100

Message-ID:

<alpine.DEB.1.10.0907192354180.13702@urchin.earth.li>

On Sun, 19 Jul 2009, Lew wrote:

I V wrote:

On Sun, 19 Jul 2009 09:44:37 -0400, Arne Vajh?j wrote:

If someone feels
like their code never throws an exception, they could tend to write an
empty exception handler:

try {
// code that is incorrectly assumed not to throw any exception
} catch(Exception e) { }

Hopefully no one writing Java code for a living.

What is the best practice for situations where you know that a particular
invocation of a function will not throw an exception that is in the
function's exception specification? Obviously an empty catch block isn't an
acceptable option. Should you put an assertion in the catch block? Or is
there some other preferred idiom?

Log the exception and return gracefully.

public void Foo()
{
  try
  {
    invokeMethodThatThrowsIOE();
  }
  catch ( IOException exc )
  {
    final String msg = "IOException: "+ exc.getLocalizedMessage();
    logger.error( msg );
    return;
  }
}

Seriously? So if a method which you were assuming would never throw an
exception threw an exception, you'd effectively shrug, mention it, and
carry on? You wouldn't hold up your hands and say "whoa, that shouldn't
happen, i'm going to stop right now"?

You could put an assertion after the catch block but it is hard to think
what one would assert inside the catch block. What would be the
invariant there?

That it's unreachable - so "assert false;" would do.

tom

--
Hit to death in the future head