[jboss-dev] findLoaded bootstrap class WAS Re: Possible blocker with jboss-cl 2.2.0.Alpha1 [WAS]: Hudson Jobs Hanging

[Adrian Brock]

On Mon, 2010-02-15 at 12:48 +0100, Carlo de Wolf wrote:
> Out of curiosity, why doesn't isLoadedClass check the boot class loader? 
> (apart from private API concerns)
> 

You mean something like:

   protected Class<?> isLoadedClass(String name, boolean trace)
   {
      // Short cut for java.* classes
      if (ClassFilterUtils.NOTHING_BUT_JAVA.matchesClassName(name))
      {
         Class<?> result = getSystemClassLoader().findLoadedClass(name);
         if (result != null)
            return result;
      }
      
      // Existing code
      Class<?> result = findLoadedClass(name);
      if (result != null)
      {

// etc

Like you say, findLoadedClass() has protected access so it would
need to use reflection to make it accessible.

We could only do that for java.* classes since all the other ones
could be in isolated/filtered classloaders meaning it wouldn't want
the version from the bootstrap classloader.

It would also only be relevant the first time this classloader
initiates a request to load the class. Once it has done it once,
the existing findLoadedClass() check should remember it
(assuming the class doesn't get garbage collected).

> Carlo
> 
> On 02/09/2010 05:01 PM, Adrian Brock wrote:
> > trunk is now using jboss-cl 2.2.0.Alpha2
> >
> > On Tue, 2010-02-09 at 09:30 -0600, Brian Stansberry wrote:
> >    
> >> LOL. Thanks; I thought this had been shifted to jboss-dev.
> >>
> >> On 02/09/2010 09:20 AM, Ales Justin wrote:
> >>      
> >>> To put this on jboss-dev.
> >>> (as Brian is probably reading emails in chronological order :-))
> >>>
> >>> The CL 2.2.0.Alpha2 was just tagged. ;-)
> >>>
> >>> On Feb 9, 2010, at 4:06 PM, Brian Stansberry wrote:
> >>>
> >>>        
> >>>> On 02/09/2010 04:50 AM, Adrian Brock wrote:
> >>>>          
> >>>>> On Mon, 2010-02-08 at 22:02 -0600, Brian Stansberry wrote:
> >>>>>            
> >>>> <snip/>
> >>>>
> >>>>          
> >>>>> There is however a change in behaviour since jboss-4.2.x in that
> >>>>> you could always load java.lang.* classes even when the classloader
> >>>>> was shutdown.
> >>>>>
> >>>>> This was because of a shortcut in the old UCL classloader:
> >>>>> http://viewvc.jboss.org/cgi-bin/viewvc.cgi/jbossas/branches/Branch_4_2/jmx/src/main/org/jboss/mx/loading/RepositoryClassLoader.java?r1=60321&r2=63960 to workaround this problem:
> >>>>> https://jira.jboss.org/jira/browse/JBAS-4536
> >>>>> which doesn't exist with the new classloader when correctly configured.
> >>>>>
> >>>>> I can restore the 4.2.x behaviour, but I don't think it
> >>>>> is the real problem?
> >>>>>
> >>>>> In both examples on JBAS-7688, it would still fail if it tried to
> >>>>> load a common/lib class at that point, e.g. javax.ejb.*
> >>>>> or any other class not in the classloader that is shutdown.
> >>>>>            
> >>>> Good point. Still, https://jira.jboss.org/jira/browse/JBCL-145 seems useful, since a lot of responses only involve JDK classes.
> >>>>
> >>>> I don't see any reason to not use jboss-cl 2.2.x in M2; the clean shutdown behavior the ejbthree1116 is testing doesn't work, which isn't the fault of jboss-cl.
> >>>>
> >>>> It would be nice though to have a jboss-cl 2.2.0.Alpha2 w/ the JBCL-145 fix to reduce the probability of this kind of failure.
> >>>>
> >>>> Thanks, everyone, for digging into this.
> >>>>          
> >>>        
> >>
> >>      
> >    
> 

-- 
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Adrian Brock
Chief Scientist
JBoss by Redhat
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