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From: Stanimir Stamenkov <s7an10@netscape.net>
Newsgroups: comp.lang.java.programmer
Subject: Re: Avoid creating a stacktrace prior to JDK 1.7
Date: Sat, 01 Oct 2011 20:31:42 +0300
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Sat, 1 Oct 2011 09:10:16 -0700 (PDT), /Lew/:
> Jan Burse wrote:
>> Stanimir Stamenkov schrieb:
>>
>>> You may perform a check which avoids the exceptional situation like:
>>>
>>> Class<?>  class;
>>> try {
>>>    class = (Class.getResource(str + ".class") != null)
>>>        ? Class.forName(str)
>>>        : null;
>>> } catch (ClassNotFoundException x) {
>>>    class = null;
>>> }
>>>
>>> The Class.forName(String) could still fail if the access to the resource
>>> content is restricted, I imagine.
>>>
>> Yes, this would change the role of exceptions,
>
> No, it would /restore/ the role of exceptions.
>
> The role of exceptions is to
>> not use it for business logic, only for
>> exceptional flow.
>
> in the first place.
>
> /Effective Java/, Joshua Bloch, "Item 57: Use exceptions only for exceptional conditions".

I don't think handling the ClassNotFoundException from 
Class.forName(String) contradicts the above statement.  In this 
exact case one may consider handling the exception a better 
alternative if the code in question is invoked multiple times with 
possibly the same class name, which class could have been 
initialized already and Class.forName() would just return the Class 
object.  The resource lookup may be more expensive operation, if 
repeated every time, just to avoid the exception.  One may also 
cache the resource lookup results.

-- 
Stanimir