RE: [ObjectWeb architecture] Java Isolation API

["Leskov, Dmitry" <dleskov@xxxxxxxxxxxxxxxxx>]

Markus,

Ok, but what are the ultimate benefits of running many apps on one VM? Are
not these memory saving and startup time? AOT compilation of classes common
to your applications into DLLs gives you both. My understanding is that the
only thing the Isolation API would add here are "means of effectively
managing multiple applications in a secure and scalable manner", whereas
with Runtime.exec() you have to invent something platform-specific or rely
on some third party components. 

Then, VM sharing in one process would compromise the overall system
reliability. Now, you run your apps one and two on two different VMs, so if
one of them crashes its VM due to a bug in the VM code or in some JNI code,
the other will continue working, whereas if they share the VM, both will
terminate abnormally. From that point of view, it is better to have separate
apps run in separate address spaces and share code and data in the
copy-on-write mode, just as it happens to native Windows executables. This
used to work well with JET-compiled DLLs on Windows NT/2000/XP.

The Isolation API can perhaps be implemented using separate processes, or
the decision of whether a separate process must be created can be left up to
the application developer. That would surely invalidate the above argument
to a considerable extent. But the discussions I have read so far revolved
around having multiple apps run in one Java VM process...

With best regards,

Dmitry

> -----Original Message-----
> From: markus.karg@xxxxxxxxx [SMTP:markus.karg@xxxxxxxxx]
> Sent: Monday, October 13, 2003 2:55 PM
> To:   architecture@xxxxxxxxxxxxx
> Subject:      Re-2: [ObjectWeb architecture] Java Isolation API
> 
> Dmitry,
> 
> thanks for the information.
> 
> For the sharing of code: This is not the idea behind that API. Instead
> what this API targets at is the ability of running many java apps in
> parallel inside the same VM instance without interfering with each other.
> This enables lightwight server implementations. If you have app one and
> app two which currently need to run in two VM instances two not interfere
> with each other (e. g. they are acting on VM resources), they now can run
> in one VM instance and such share one OS task while still beeing insulated
> from each other.
> 
> Have Fun
> Markus
> 
> -------- Original Message --------
> Subject: RE: [ObjectWeb architecture] Java Isolation API (13-Okt-2003
> 9:50)
> From:    dleskov@xxxxxxxxxxxxxxxxx
> To:      markus.karg@xxxxxxxxx
> 
> > Markus,
> > 
> > Sorry to disappoint you, but JSR 121 is NOT listed in the updated
> version 
> > of
> > clause 3.1 of JSR 176 "J2SE 1.5 (Tiger) Release Contents", so it will
> not
> > even be considered for evaluation:
> > 
> > http://www.jcp.org/en/jsr/detail?id=176
> > 
> > This had sparked protests in Java developer communities - see e.g.
> > http://www.javalobby.org/thread.jsp?forum=61&thread=8563
> > 
> > Besides, with ahead-of-time compilers one could begin using DLLs/shared 
> > libs
> > for sharing code and static data between applications at the OS level
> years
> > ago.
> > 
> > With best regards,
> > 
> > Dmitry
> > 
> > > -----Original Message-----
> > > From:     Markus Karg [SMTP:markus.karg@xxxxxxx]
> > > Sent:     Saturday, October 11, 2003 12:59 AM
> > > To:       architecture@xxxxxxxxxxxxx
> > > Subject:  [ObjectWeb architecture] Java Isolation API
> > > 
> > > I just stumbled over that "Java Isolation API" that will propably come
> > > with 
> > > Java 1.5. It enables running more than one Java Application per VM. It
> is 
> > > namely told the possibility of running independent daemons inside of
> one 
> > > single VM which was started at the machine's boot time. Maybe this is
> an 
> > > interesting aspect for future ObjectWeb architecture. AFAIK the API is
> > > found 
> > > under JSR 121.
> > > 
> > > Have Fun
> > > Markus
> > >  << File: message.footer >> 
> > 
> > 
> > 
> > To: markus.karg@xxxxxxx
> >     architecture@xxxxxxxxxxxxx
> 
>  << File: message.footer >>