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Re: "Small" Program Challenge.

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On 25/06/2012 3:59 PM, Lew wrote:
> javax.swing.JSnarker wrote:
>> Daniel Pitts wrote:
>>> How I would expect this to work in reality.
>>>
>>> 1. Load class
>>> 2. get a reference to the static method "void main(String[])"
>>> 3. Attempt to execute that reference
>>>      3.1 Causes class initialization before execution.
>>>      3.2 actual execution occurs.
>>
>> That has a problem, though, in that class initialization will happen on
>> every method call, resulting in multiple initializations, if it's part
>
> That's not what happens.

I'm not finished. Class initialization will happen on every method call, 
resulting in multiple initializations, *if it's part* of "attempt to 
execute the reference" rather than (as the spec says) something the JVM 
does immediately *before* the first such attempt (or other action that 
requires an initialized class for the action to begin).

> As the spec says, it happens upon the first attempt to execute a static method
> (if the class has not already been initialized).

No, the spec does not say "upon" it says "immediately before".

>> I suppose you could change 3.1 to "see if the class is initialized, and
>> if not, initialize it", but even that would add to *every method call*
>
> That is what the spec says to do. As previously linked.
>
>> the overhead of a test-and-branch, and would still be dodgy at best on
>> spec-adherence grounds.
>
> No, it does what it does and adheres to the spec.

No, what the spec says to do is to implement a statically-compiled call 
this way:

Class is loaded and initialized by statically-compiled code.
Method invocation is simply a bare invokestatic instruction

And a reflective/otherwise non-static call this way:

Check if class is loaded and if not load and verify it.
Check if class is initialized and if not initialize it.
Check if method exists and if not throw an exception, otherwise invoke it.

And this is apparently what earlier versions did.

Surely you aren't suggesting there's a whole raft of if 
(class_is_loaded), if (class_is_initialized), etc. tests before every 
method call in Java 7? Because that would make method calls much slower 
than before, unless you've got some cleverness in place to remove those 
tests from the code once the class is loaded. In other words, something 
more like expanding each call into

load_and_initialize_if_needed(X.class);
invokestatic...

where load_and_initialize_if_needed(X.class) strips out all instances of 
load_and_initialize_if_needed(X.class) from all loaded bytecode as part 
of its own behavior. But that would have all kinds of difficulties of 
its own. At least the JIT might be able to skip over it if X is already 
loaded and an instance is in code it's JITting.

-- 
public final class JSnarker
extends JComponent
A JSnarker is an NNTP-aware component that asynchronously provides 
snarky output when the Ego.needsPuncturing() event is fired in cljp.

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"Small" Program Challenge. Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-06-13 13:45 -0700
  Re: "Small" Program Challenge. Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-06-13 13:52 -0700
    Re: "Small" Program Challenge. Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-06-13 16:17 -0700
      Re: "Small" Program Challenge. glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-06-14 00:16 +0000
    Re: "Small" Program Challenge. Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-06-13 16:19 -0700
      Re: "Small" Program Challenge. Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-06-13 16:24 -0700
    Re: "Small" Program Challenge. markspace <-@.> - 2012-06-13 17:40 -0700
  Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-13 21:28 -0400
  Re: "Small" Program Challenge. Roedy Green <see_website@mindprod.com.invalid> - 2012-06-13 20:52 -0700
    Re: "Small" Program Challenge. "Hiram Hunt" <hiramhunt@verizon.net> - 2012-06-14 08:23 -0400
      Re: "Small" Program Challenge. "Hiram Hunt" <hiramhunt@verizon.net> - 2012-06-14 08:30 -0400
    Re: "Small" Program Challenge. Arne Vajhøj <arne@vajhoej.dk> - 2012-06-17 21:17 -0400
  Re: "Small" Program Challenge. Paul Cager <paul.cager@googlemail.com> - 2012-06-14 02:32 -0700
  Re: "Small" Program Challenge. Bent C Dalager <bcd@pvv.ntnu.no> - 2012-06-14 11:29 +0000
  Re: "Small" Program Challenge. Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-06-14 12:50 -0700
  Re: "Small" Program Challenge. Leif Roar Moldskred <leifm@dimnakorr.com> - 2012-06-14 15:49 -0500
  Re: "Small" Program Challenge. Gene Wirchenko <genew@ocis.net> - 2012-06-14 14:56 -0700
  Re: "Small" Program Challenge. Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-06-14 17:02 -0700
  Re: "Small" Program Challenge. Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-06-14 17:09 -0700
  Re: "Small" Program Challenge. Kevin McMurtrie <mcmurtrie@pixelmemory.us> - 2012-06-15 22:13 -0700
    Re: "Small" Program Challenge. Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-06-16 12:11 -0700
  Re: "Small" Program Challenge. Wanja Gayk <brixomatic@yahoo.com> - 2012-06-17 15:22 +0200
    Re: "Small" Program Challenge. Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-06-17 15:24 -0700
      Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-17 18:25 -0400
        Re: "Small" Program Challenge. Arne Vajhøj <arne@vajhoej.dk> - 2012-06-17 20:31 -0400
          Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-17 20:55 -0400
            Re: "Small" Program Challenge. Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-06-17 20:40 -0700
              Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-17 23:43 -0400
              Re: "Small" Program Challenge. Lew <noone@lewscanon.com> - 2012-06-17 21:25 -0700
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-18 00:45 -0400
                Re: "Small" Program Challenge. Lew <lewbloch@gmail.com> - 2012-06-18 12:47 -0700
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-18 15:57 -0400
                Re: "Small" Program Challenge. Lew <lewbloch@gmail.com> - 2012-06-18 13:31 -0700
                Re: "Small" Program Challenge. Leif Roar Moldskred <leifm@dimnakorr.com> - 2012-06-18 16:05 -0500
                Re: "Small" Program Challenge. Lew <lewbloch@gmail.com> - 2012-06-18 14:18 -0700
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-18 19:50 -0400
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-18 19:48 -0400
                Re: "Small" Program Challenge. David Lamb <dalamb@cs.queensu.ca> - 2012-06-19 08:07 -0400
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-19 15:26 -0400
                Re: "Small" Program Challenge. Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-06-18 09:04 -0700
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-18 13:09 -0400
                Re: "Small" Program Challenge. markspace <-@.> - 2012-06-18 11:06 -0700
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-18 14:46 -0400
                Re: "Small" Program Challenge. markspace <-@.> - 2012-06-18 13:22 -0700
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-18 19:51 -0400
                Re: "Small" Program Challenge. Wanja Gayk <brixomatic@yahoo.com> - 2012-06-20 13:11 +0200
                Re: "Small" Program Challenge. Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-06-22 12:54 -0700
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-22 18:30 -0400
                Re: "Small" Program Challenge. Lew <lewbloch@gmail.com> - 2012-06-25 12:59 -0700
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-25 16:49 -0400
                Re: "Small" Program Challenge. Lew <lewbloch@gmail.com> - 2012-06-18 12:44 -0700
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-18 16:01 -0400
                Re: "Small" Program Challenge. Lew <lewbloch@gmail.com> - 2012-06-18 13:36 -0700
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-18 20:01 -0400
                Re: "Small" Program Challenge. Lew <lewbloch@gmail.com> - 2012-06-18 18:25 -0700
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-18 22:01 -0400
                Re: "Small" Program Challenge. Gene Wirchenko <genew@ocis.net> - 2012-06-18 19:04 -0700
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-18 22:12 -0400
                Re: "Small" Program Challenge. Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2012-06-19 12:36 +0000
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-19 15:28 -0400
                Re: "Small" Program Challenge. Gene Wirchenko <genew@ocis.net> - 2012-06-19 09:12 -0700
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-19 15:30 -0400
                Re: "Small" Program Challenge. Gene Wirchenko <genew@ocis.net> - 2012-06-19 15:04 -0700
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-19 18:23 -0400
                Re: "Small" Program Challenge. Gene Wirchenko <genew@ocis.net> - 2012-06-19 15:32 -0700
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-19 19:09 -0400
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-19 19:10 -0400
                Re: "Small" Program Challenge. Lew <lewbloch@gmail.com> - 2012-06-19 17:19 -0700
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-19 20:42 -0400
                Re: "Small" Program Challenge. Leif Roar Moldskred <leifm@dimnakorr.com> - 2012-06-19 20:01 -0500
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-19 21:12 -0400
                Re: "Small" Program Challenge. Leif Roar Moldskred <leifm@dimnakorr.com> - 2012-06-19 20:32 -0500
                Re: "Small" Program Challenge. Lew <noone@lewscanon.com> - 2012-06-19 22:01 -0700
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-20 21:15 -0400
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-20 21:05 -0400
                Re: "Small" Program Challenge. Wanja Gayk <brixomatic@yahoo.com> - 2012-06-23 13:42 +0200
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-23 12:12 -0400
                Re: "Small" Program Challenge. Wanja Gayk <brixomatic@yahoo.com> - 2012-06-23 23:10 +0200
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-23 17:14 -0400
                Re: "Small" Program Challenge. Lew <noone@lewscanon.com> - 2012-06-19 22:15 -0700
                Re: "Small" Program Challenge. Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2012-06-20 10:34 +0000
                Re: "Small" Program Challenge. Lew <lewbloch@gmail.com> - 2012-06-20 10:45 -0700
                Re: "Small" Program Challenge. Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2012-06-21 08:13 +0000
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-21 17:18 -0400
                Re: "Small" Program Challenge. Lew <lewbloch@gmail.com> - 2012-06-21 15:30 -0700
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-21 20:28 -0400
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-20 21:22 -0400
                Re: "Small" Program Challenge. "javax.swing.JSnarker" <gharriman@boojum.mit.edu> - 2012-06-20 21:19 -0400

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