Re: [aspectj-users] Weaving already loaded classes

[Alexandre Vasseur <avasseur@xxxxxxxxx>]

back 2 years ago I had implemented a "remote hotswap" feature to
enable AspectWerkz weaving remotely after startup
(http://aspectwerkz.codehaus.org/weaving.html#Remote_HotSwap)

that is fun, but in absolute not that usefull, as when you have done
that it becomes unclear what aspect will be weaved in where -
My use case for that was:
- start app as usual, with a bunch of troubleshooting aspect ready
around (but not weaved in)
- let it run
- enable weaver remotely with remote hotswap
- redeploy some sub apps so that the troubleshooting aspects get deployed

I think late binding of agent makes total sense for non instrumenting
ones, but that is more debatable for instrumenting ones (as you still
need a redeploy and the actual scope of the so simulated hot
deployment of your aspect becomes unclear).
IMHO it's a try to match what a true dynamic weaver can do.

Alex



On 12/23/05, mohan.radhakrishnan@xxxxxxxxxxxxx
<mohan.radhakrishnan@xxxxxxxxxxxxx> wrote:
>
> Hi,
>      Yes. It seems that this API was designed for profiling. Actually I
> started poking around this when I found there is a way to use Mustang
> jconsole to an already running VM and monitor using JMX/AOP(GlassBox
> Inspector) even if you don't start the JSE 5.0 VM with
> -Dcom.sun.management.jmxremote.
>
> So when I read that a java agent can be loaded on an already running VM
> using the Attach API in mustang, I though it could be of use to AOP.
>
> Thanks,
> Mohan
>
> -----Original Message-----
> From: aspectj-users-bounces@xxxxxxxxxxx
> [mailto:aspectj-users-bounces@xxxxxxxxxxx] On Behalf Of Alexandre
> Vasseur
> Sent: Friday, December 23, 2005 4:01 AM
> To: aspectj-users@xxxxxxxxxxx
> Subject: Re: [aspectj-users] Weaving already loaded classes
>
> Mohan
>
> My personnal opinion:
> This is actually an attempt from the JSR-163 folks to solve the complex
> problem of multiple weaving that I and others had raised 2 years ago.
> Retransform is aiming at handling the non retransform capable agents
> (see the agent manifest doc)
>
> Sadly, this is really going into hell (see also the tricks to rename
> native method and making sure native pointer to the native impl.
> beehind are kept in sync by the VM - needed f.e. to do an around like
> advice on a native method execution - required by some profiling tool
> vendor out there) while we have demonstrated what could be done by
> forgetting about bytecode and moving things into the VM directly.
> See our standpoint on that f.e. in
> http://dev2dev.bea.com/pub/a/2005/08/jvm_aop_1.html (shameless plug)
>
> Alex
>
>
>
>
> On 12/22/05, mohan.radhakrishnan@xxxxxxxxxxxxx
> <mohan.radhakrishnan@xxxxxxxxxxxxx> wrote:
> > Hi,
> >        Any idea if this is useful
> > http://download.java.net/jdk6/docs/api/java/lang/instrument/Instrument
> > ation.html#retransformClasses(java.lang.Class...)
> > ?
> > This is a mustang feature called late-binding agent support.
> >
> > Thanks,
> > Mohan
> >
> >
> >
> >
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