[jboss-as7-dev] Question about EAR's and Class Loading

[Jason T. Greene]

On 3/22/11 3:08 PM, Jason T. Greene wrote:
> On 3/22/11 2:58 PM, David M. Lloyd wrote:
>> On 03/22/2011 02:51 PM, David M. Lloyd wrote:
>>> On 03/22/2011 02:42 PM, Andrig Miller wrote:
>>>>> If OrderManagerEntities.jar is in the EAR's "lib" directory (or the
>>>>> directory you have configured as such in application.xml) then the
>>>>> OrderManagerEJB.jar should be able to "see" it. If not then you'll
>>>>> need
>>>>> an explicit "Class-Path" reference to it from your EJB JAR.
>>>>
>>>> No, my OrderManagerEntities.jar is not the EAR's "lib" directory,
>>>> its at the same level as the OrderManagerEJB.jar, and its listed as
>>>> an EJB module in the application.xml.
>>>>
>>>> This seems broken to me.
>>>
>>> As a rule, we are restricting visibility by default as much as the spec
>>> allows (which may mean certain behaviors are different from AS 5/6). So
>>> the question is really, is this contrary to spec? If so, it's a bug.
>>> That's what we need to answer.
>>
>> Here's the relevant passage:
>>
>> "Components in the EJB container may have access to the following
>> classes and resources. Portable applications must not depend on having
>> or not having access to these classes or resources.
>> [...]
>> * The content of any EJB jar files included in the same ear file.
>> * The content of any client jar files specified by the above EJB jar
>> files."
>>
>> Thus it is correct to require an explicit Class-Path between EJB JARs
>> within an application.
>
> Note that its typically not required if you are using injection / jndi,
> because then you are wiring a dependency and passing instances along
> module boundaries.
>
> In the JPA case though, its just local classes, so their needs to be
> some kind of import (/lib, class-path ref, module-ref) in our current
> low-visibility model.

BTW the reason we went with the low-visibility model, was that our 
thinking was it would reduce CCEs and allow for multiple EJB jars to use 
different versions of a thirdparty framework in the same EAR.

-- 
Jason T. Greene
JBoss, a division of Red Hat