Re: [aspectj-users] debugging without stopping server

["Andrew Eisenberg" <andrew@xxxxxxxxxxxx>]

I think I am beginning to see what you want.  You want to take a
server that is already running, and without stopping it, add some
aspects to it that will perform logging and tracing.  Is that right?
Unfortunately, this is not the way normal AspectJ load time weaving
works.  All classes and aspects must be available at boot time.

So, the server must be brought down, and restarted with the aspects on
the classpath and using the appropriate java agent and aop,xml.

However, there are some technologies that allow dynamic deployment of
aspects like Equinox aspects and Spring dynamic server, but they both
require that you use OSGi as an underlying architecture.  Similarly,
this is how AspectWerkz and JBoss worked.

On Sat, Sep 13, 2008 at 6:54 AM, Neo Anderson
<javadeveloper999@xxxxxxxxxxx> wrote:
> Hi Simone,
>
> Thanks for spending time to explain it. : )
>
> But I think there is still something I do not understand very well and want to make it clear.
>
> In fact, I have successfully get load-time weaving example worked (http://www.nabble.com/Load-time-weaving-problem-tt19347338.html#a19357654). So I think I have some basic ideas about how load-time weaving processes. However, it looks like it is based on each time when a new jvm is launched (via executing `java -javaagent:...`), weaving aspect to the target classes. Now suppose if I have a server already running, it may execute command like 'java -classpath ....' or 'java -javaagent:...' (all is based on jdk 5.0 or higher version). If I want to capture/ trace information as you described below, what should I do in order to achieve it without stopping the server?
>
> For instance, I programme a mock server which only prints count on the screen (source is as A). How can I hook my aspect to capture when counter is equals to 7 (Then do something defined in the aspect like tracing or log value to somewhere, etc.) I completely have no idea about this (As I understand is this is run-time/ online weaving, which aspectj does not support, but aspectwerkz does, which now is merged with aspectj.) Would you please to give me a bit more explain on this (or some steps to perform this)? Or kindly pointing me where there contains such document for aspectj.
>
> I sincerely appreciate your help.
>
> A.)
> package sys;
>
> public class Server{
>        private static int count = 0;
>
>        private synchronized void start(){
>                try{
>                        while(true){
>                                System.out.println("count:"+count);
>                                count++;
>                                new Thread().sleep(1000);
>                        }
>                }catch(Exception e){
>                        e.printStackTrace();
>                }
>        }
>
>        public static void main(String args[]){
>                new Server().start();
>        }
> }
>
>