[rules-dev] Questionable Exception Handling

[Mark Proctor]

I'll fix in trunk soon.

Mark
Greg Barton wrote:
> I have to agree with Zoltan on this one.  Catching
> Throwable is ungood.
>
> --- Mark Proctor <mproctor at codehaus.org> wrote:
>
>   
>> If no one is agueing for Throwable, I'll update it
>> to Exception then.
>>
>> Mark
>> Zoltan Farkas wrote:
>>     
>>> This is my opinion also and is in line with the
>>>       
>> java best practices...
>>     
>>> Based on javadoc(see class Error and Exception):
>>>
>>> "The class Exception and its subclasses are a form
>>>       
>> of Throwable that indicates conditions that a
>> reasonable application might want to catch. "
>>     
>>> "An Error is a subclass of Throwable that
>>>       
>> indicates serious problems that a reasonable
>> application should not try to catch."
>>     
>>> In all my apps I want my application to stop on a
>>>       
>> unrecoverable error (like OOM). However since most
>> libraries have some catch(Throwable) in the code, I
>> always have to use: 
>>     
>>> -XX:+HeapDumpOnOutOfMemoryError
>>>       
>> -XX:HeapDumpPath=${DUMP_PATH}
>> -XX:OnOutOfMemoryError="kill -9 %p"
>>     
>>> For me as a user of the drools engine as a 3rd
>>>       
>> party I would expect that Error not be "hidden"
>> inside a RuntimeException. For me Errors are
>> something I cannot recover from... however I might
>> choose to continue the application on a Exception
>> ...
>>     
>>> This is my opinion on this...
>>>
>>> thanks
>>>
>>> --zoly
>>>
>>>
>>> ________________________________________
>>> From: rules-dev-bounces at lists.jboss.org
>>>       
>> [mailto:rules-dev-bounces at lists.jboss.org] On Behalf
>> Of Geoffrey Wiseman
>>     
>>> Sent: Friday, April 04, 2008 2:10 PM
>>> To: Rules Dev List
>>> Subject: Re: [rules-dev] Questionable Exception
>>>       
>> Handling
>>     
>>> In most cases, I'd say that Errors shouldn't even
>>>       
>> be caught and rethrown, personally -- something like
>> an OOME doesn't need additional object creation, for
>> instance.
>>     
>>> On Fri, Apr 4, 2008 at 1:55 PM, Mark Proctor
>>>       
>> <mproctor at codehaus.org> wrote:
>>     
>>> I don't see a problem with Throwable there? We
>>>       
>> rethrow again, adding in some additional
>> information. I found that just catching Exception
>> didn't work as you could get verification errors and
>> other stuch things. If you look at the context of
>> that that method is doing too, its using reflection
>> to instantiate a class.
>>     
>>> Mark
>>> Zoltan Farkas wrote: 
>>> I was browsing through the drools source code 
>>>  
>>> I am not a fan of seeing catching Throwable in any
>>>       
>> java code ...
>>     
>>>  
>>> I see this in class org.drools.util.ClassUtils:
>>>  
>>>     /**
>>>      * This method will attempt to create an
>>>       
>> instance of the specified Class. It uses
>>     
>>>      * a syncrhonized HashMap to cache the
>>>       
>> reflection Class lookup.
>>     
>>>      * @param className
>>>      * @return
>>>      */
>>>     public static Object instantiateObject(String
>>>       
>> className) {
>>     
>>>         Class cls = (Class)
>>>       
>> ClassUtils.classes.get( className );
>>     
>>>         if ( cls == null ) {
>>>             try {
>>>                 cls = Class.forName( className );
>>>                 ClassUtils.classes.put( 
>>>       
>> className, cls );
>>     
>>>             } catch ( Throwable e ) {
>>>                 throw new RuntimeException("Unable
>>>       
>> to load class '" + className + "'", e );
>>     
>>>             }            
>>>         }
>>>         
>>>         Object object = null;
>>>         try {
>>>             object = cls.newInstance();           
>>>       
>>>         } catch ( Throwable e ) {
>>>             throw new RuntimeException("Unable to
>>>       
>> instantiate object for class '" + className + "'", e
>> );
>>     
>>>         }  
>>>         return object;
>>>     }
>>>  
>>> I believe this masks important errors where the
>>>       
>> application should not continue to run and it would
>> be preferable to crash...
>>     
>>>  
>>> --zoly
>>>  
>>> ________________________________________
>>>
>>> _______________________________________________
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>>> rules-dev at lists.jboss.org
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>>>   
>>>
>>>
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>>>
>>>
>>>
>>>   
>>>       
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>>
>>     
>
>
>
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