[OpenJDK 2D-Dev] <AWT Dev> Review Request for 6879044

[Mandy Chung]

Hi Oleg,

A better question to ask is who and how the logging information AWT is 
used for.   The AWT team confirms that the AWT loggers are for debugging 
purpose used by the awt developers.  As specified in the Requirements 
chapter for the Java Logging Spec (JSR-47) [1], the central goal of the 
logging API is to support maintaining and servicing software at customer 
sites.   Adding debugging code in the awt implementation using logging 
API is reasonable but it's not the requirement for the logging API.  If 
there were a better option to add debugging code, I believe you have no 
problem changing the awt debugging code not to use the logging API.

Server-type applications are typical use cases that logging information 
is very important and useful for diagnosis in the field - long running 
apps, hard to reproduce problems until running for many days/months.  It 
is hard to imagine how the logging information is important in client 
applications.   But you seem to know many client applications use the 
logging API that I would also be interested to follow up with their 
requirements.

>
> Ok, so this fix is only about modules.  But why AWT should not depend
> on logging module?
> The qiestion is: how many application we want to run doesn't use
> logging& Because if an application
> uses logging there is no reasons for AWT to not use it.  Please note
> that even if logging is turned
> off, the application still needs logging package/module.  So, though
> end-user doesn't need logging output
> she may need logging module to run the application.  

This is exactly why we want to decouple the dependency on logging.  When 
an application uses logging, the application knows clearly what module 
they require and that's fine.  When an application doesn't logging, if 
the awt component requires logging for debugging purpose only, it 
increases the download size, footprint and startup performance (class 
lookup time, loading, init, etc) - please see my performance analysis 
report; otherwise, it's not fruitful to discuss the details in this 
thread without the background info.  Just to mention it what we care about.

> So, it is really
> important to understand
> what number of application will get advantage of suggested changes.
>
>   

You are suggesting the client applications always have a dependency on 
logging.   Many client team engineers are happy to see the dependency on 
logging being eliminated from the client stack requirement and approve 
this fix :)

> Second question is: how big logging module is going to be? How big the
> benefit for end-user will be?
>
>   

The size of the logging API is not big (~90K) but the size is not the 
only one factor determining what benefit the end-user will have.   It's 
not necessary to logging API as one single module and details are to be 
worked out.   Subscribe to the jigsaw project to follow the discussion 
and progress there.   Serviceability includes other API as well.  If awt 
started using other serviceability API (java.lang.management, 
java.lang.instrument) for whatever reason, your argument would apply 
there as well.  I don't think you wanted the awt module depends on all 
the serviceability APIs.

> I'm asking so many question mainly because the changes you suggested
> create rather unnatural code (we can not
> use standard logging machinery any more), so such changes should be
> well-justified.
>
>   

That's what we pay for to modularize the JDK after many years of JDK 
development without module support in the platform.  Otherwise, if there 
were module support in the platform, you would consider very carefully 
when adding a dependency on another module.

If you have further issue, I suggest to start a different thread on the 
awt-dev alias.

Thanks
Mandy
[1] http://jcp.org/aboutJava/communityprocess/first/jsr047/index.html