Hi Kedar
We've got Glassbox (which uses AspectJ LTW) to be running very well on
GlassFish with the proposed change, for our JavaOne 2007 Hands-On Lab
1420. You can refer to Sun Developer Network (SDN) JavaOne 2007 Online
Hands-On Lab 1402
<
http://developers.sun.com/learning/javaoneonline/j1lab.jsp?lab=LAB-1420&yr=2007&track=5>
for more details of our lab and configurations instructions for GlassFish.
Btw, is there a recommended limit on the length of GlassFish's system
classpath? Can you elaborate more on the issues regarding length of
system classpath?
Thanks
Max
Kedar Mhaswade wrote:
> Max,
>
> I think this is a valid concern. Though I am not a 100% sure, one of
> the reasons these classes
> are not on the system classpath is to reduce the length of the
> classpath which was known to
> cause some issues. Currently, only the PELaunch and few other classes
> are available in the system-classpath and
> as such is loaded by the System CL. The rest is taken care of by the
> classloading mechanism that
> is documented extensively (Also read Sivakumar Thyagarajan's Blog).
>
> Frankly, I don't see any issues with this proposal. Can you give it a
> try and see if it works?
>
> Kedar
>
> Max Poon wrote:
>> Greetings *
>>
>> Is the any specific reason why JavaDB (org.apache.derby.*) classes
>> are loaded via Extensions ClassLoader instead of System ClassLoader
>> in GlassFish, since Extensions ClassLoader seems to be used for
>> loading optional packages to core Java packages, mostly the javax.*
>> classes ?
>>
>> From JDK documentation on Java Extension Mechansim :
>>
>> "Optional packages are the new name for what used to be known as
>> /standard extensions/. The "extension mechanism" is that
>> functionality of the JDK and JRE that supports the use of optional
>> packages.
>> .......
>> A optional package is an implementation of an open, standard API
>> (examples of optional packages from Sun are JavaServlet
>> <http://java.sun.com/products/servlet>, Java3D
>> <http://java.sun.com/products/java-media/3D>, JavaManagement
>> <http://java.sun.com/products/JavaManagement/>). Most optional
>> packages are rooted in the javax.* namespace, although there may be
>> exceptions."
>>
>> Especially in case of deploying AspectJ applications where the
>> AspectJ weaver is loaded in GlassFish's System ClassLoader via the
>> Java language agent (-javaagent:xxx.jar), the application classes
>> weavable with AspectJ are limited to those which can "see" the
>> AspectJ weaver classes and the aspects being weaved which are
>> typically loaded in GlassFish's System ClassLoader. Loading database
>> driver related (e.g. Derby) classes via Extension ClassLoader will
>> render weaving on those classes not possible. This seems to be in
>> sync with the strategy with loading of "non-core" classes via
>> Bootstrap or Extension ClassLoader should be minimized.
>>
>> This will also facilitate deployment of AspectJ weaving applications
>> on GlassFish. For example, we explicitly modified GlassFish's
>> jvm-options to have derby jars and classes loaded via GlassFish's
>> System ClassLoader to enable JDBC connection and statement execution
>> monitoring by GlassBox <http://glassbox.com> on GlassFish, which may
>> be by default enabled on other web containers like Tomcat without
>> similar jvm-option modification needed :
>>
>> The following 3 additional jars are required to be entered and
>> included in the AppServer Class Path configuration
>>
>> * ${com.sun.aas.derbyRoot}/lib/derby.jar
>> * ${com.sun.aas.derbyRoot}/lib/derbyclient.jar
>> * ${com.sun.aas.derbyRoot}/lib/derbynet.jar
>>
>> The following string is required to be deleted from -Djava.ext.dir
>> JVM option
>>
>> * ${path.separator}${com.sun.aas.derbyRoot}/lib
>>
>> so that java.ext.dir is now
>>
>> *
>> -Djava.ext.dirs=${com.sun.aas.javaRoot}/jre/lib/ext${path.separator}${com.sun.aas.instanceRoot}/lib/ext
>>
>>
>>
>> Appreciate any comments/advice.
>>
>> Thanks
>> Max
>>
>
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