[rules-users] drools 6 and osgi

[Florian Pirchner]

Hi Mark,

i did some research. Indeed a very complex issue.
Tried to find out the difference about Class.forName(String) and 
Class.forName(String, boolean, ClassLoader). Both of them are delegating 
to native jvm methods and the difference seems to be in resolving the 
class and the way that caches work.

In http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6500212 they are 
pointing to use Class.forName(String, boolean, ClassLoader). Could find 
that method call in some drools and jbpm classes. For instance compiler...

But there are also a lot of Class.forName(String) calls too. Specialy in 
parts of code where no array-types come into play.
For instance JavaHandlerWorkItemHandler calls (Class<JavaHandler>) 
Class.forName(className).

Maybe it would be a good idea to replace Class.forName() for issues that 
exclude array-types by classloader.loadClass().

WDYT?

Best Florian



Am 20.06.13 17:28, schrieb Mark Proctor:
> There are bugs with loadClass and serialisation :(
> http://lists.jboss.org/pipermail/rules-dev/2011-November/003681.html
>
> http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6500212
> "Thus, we highly recommend replacement of this code:
>    myClassLoader.loadClass(className);
>
> With this code:
>
>    Class.forName(className,false,myClassLoader);"
>
> Mark
> On 20 Jun 2013, at 15:01, Florian Pirchner <florian.pirchner at gmail.com 
> <mailto:florian.pirchner at gmail.com>> wrote:
>
>> Hi,
>>
>> i also saw all the Class.forName. Class.forName additionally uses a very
>> aggressive class caching policy.
>> See here:
>> http://blog.osgi.org/2011/05/what-you-should-know-about-class.html
>> http://blog.bjhargrave.com/2007/09/classforname-caches-defined-class-in.html
>>
>> I do not understand why API imports compiler.impl? Maybe to enable
>> class#forname i guess.
>>
>>
>> Is there an intention to use a more modularized way in v6 beta4 when
>> OSGi support will be implemented?
>>
>> Thanks Florian
>>
>>
>> Am 20.06.13 15:43, schrieb Cristiano Gavião:
>>> Hi,
>>>
>>> Well, besides the fact that the services that we used on version 5.x is
>>> still there, I'm not that optimist with Drools 6 running well in an OSGi
>>> container... at least not currently...
>>>
>>> Last week I played a bit too with Jbosgi and Wildfly and got a lot of
>>> classloading errors due some factory classes trying to load classes that
>>> are in another bundles...
>>>
>>> what surprise me most was that kie-api has an import to
>>> org.drools.compiler.kie.builder.impl ! :)
>>>
>>> regards,
>>>
>>> John
>>> On 17/06/13 19:39, Florian.Pirchner wrote:
>>>> hi,
>>>>
>>>> i got a question about osgi support.
>>>> is beta 3 already useable in osgi environments? could see that 
>>>> activators are registering v5 api as services.
>>>>
>>>> is it possible to consume osgi services in the script tasks and 
>>>> rules by context? is this planned for version 6? would be a great 
>>>> feature.
>>>>
>>>> thanks a lot for answer
>>>> florian
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>>
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-- 
Mit besten Grüßen
Florian Pirchner
Fohlenweg 22
2301 Probstdorf
Tel: +43 650 7772338
florian.pirchner at gmail.com

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