This is one of those SS!=DS discussions which means that variables
placed/alloc'ed on the stack are NOT the same as variables alloc'ed from heap
so
when using a variable which is alloced on the stack AND initialised to some
known value (null)
feel free to test that pre-allocated stack variable as with if(stack_variable
== null)
If you dont know how this variable is alloc'ed or you know that the variable is
alloc'ed from heap use try / catch(NullPointerException npe)
to do otherwise you're risking your webapp causing 'an unhandled exception'
when referencing a unalloc'ed variable..
GL,
M-
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----- Original Message -----
From: "Steve R Burrus" <[EMAIL PROTECTED]>
To: "Tomcat Users List" <users@tomcat.apache.org>
Sent: Wednesday, November 15, 2006 2:35 PM
Subject: Re: How do I ........?
> just a tiny correction for you Chris, and that is that the code ought to
> be "if(in = = null)" not as u had it "if(null = = in)". Am I right or not?
>
> Christopher Schultz wrote:
>
>>-----BEGIN PGP SIGNED MESSAGE-----
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>>Steve,
>>
>>Steve R Burrus wrote:
>>
>>
>>>hi chris this is steve Burrus and the line of code in question is the
>>>while loop : "while( ( r = in.read(by)) != -1) {" the server error for a
>>>long time has always pointed to that line of code creating the NPE.
>>>
>>>
>>
>>Yup, that's the first time you use the InputStream after attempting to
>>load your file. It's pretty simple to check for null: just use the code
>>I suggested in my last message:
>>
>>
>>
>>>>Correct me if I'm wrong, but this generally checks for null:
>>>>
>>>>if(null == in)
>>>> // handle the null condition
>>>>
>>>>
>>
>>Now, it's up to you what you want to do in the event of a NULL image.
>>You could either return a "404 Not Found" error status, or return a
>>known good image that actually says "ERROR" on it.
>>
>>- -chris
>>
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>>=G5GE
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>
