Code Review Request: 7164636: (prefs) Cleanup src/macosx/classes/java/util/prefs

[Chris Hegarty]

I always thought that removing these superfluous "default" values would 
be a good clean up opportunity.

Maybe one to be added to the warnings/StringBuilder potential cleanup 
targets for external folks?

-Chris.

On 14/05/12 17:41, Brian Goetz wrote:
>  From a concurrency perspective it is also preferable to NOT initialize
> variables to their default values, as doing so can cause some weird
> problems. For example:
>
> class A {
> public int x = 0;
>
> public void increment() { ++x; }
> public int get() { return x; }
> }
>
> // Thread X
> // Assume: Thread X never touches 'a' again
> A a = new A();
>
> // Thread Y
> // Assume: No other thread than Y touches 'a'
> if (a != null) {
> a.increment();
> System.out.println(a.get());
> }
>
> With the explicit initialization, this code could print zero (because
> the set of writes to 'x' contains two writes, one by X to zero and one
> by Y to 1), whereas without the explicit initialization, it would always
> print one.
>
> Now, this is an example of "improper publication" of the A by Thread X,
> but this is the sort of improper publication (where an object was
> initialized by one thread and then "handed off" to another) that was
> widely thought to be safe a long time ago and was enshrined in many
> examples, particularly Swing examples.
>
> The sharing here is clearly wrong, but the approach of not unnecessarily
> initializing non-final fields eliminates a path to tickling the improper
> publication into actually producing the wrong result.
>
> On 5/14/2012 5:28 AM, Chris Hegarty wrote:
>> This change looks fine to me.
>>
>> Trivially, changedFiles and cachedFiles do not need to be set to null (I
>> believe this will generate a little less bytecode), as this is the
>> default reference value. Since you are in clean-up mode ;-)
>>
>> -Chris.
>>
>> On 11/05/2012 22:46, Kurchi Hazra wrote:
>>> Hi,
>>>
>>> This change aims at removing some rawtype usages in
>>> src/macosx/classes/java/util/prefs that were brought
>>> into jdk8 with the macport. I have added @Override tags too where
>>> applicable.
>>>
>>> Bug: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7164636
>>> Webrev: http://cr.openjdk.java.net/~khazra/7164636/webrev.00/
>>>
>>>
>>> Thanks,
>>> Kurchi
>>>