RFR: 8286663: Resolve IDE warnings in WTrayIconPeer and SystemTray

[Sergey Bylokhov]

On Mon, 23 May 2022 17:18:17 GMT, Phil Race <prr at openjdk.org> wrote:

>> **WTrayIconPeer**: removed duplicate call to `popupParent.dispose()` that might cause NPE (it looks `popupParent` cannot be `null`); organised imports.
>> 
>> **SystemTray**: removed redundant initialisers; replaced sized array with empty array in `toArray` call; dropped `newValue != null` chained with `equals`.
>
> src/java.desktop/share/classes/java/awt/SystemTray.java line 349:
> 
>> 347:         if (icons != null) {
>> 348:             return icons.toArray(new TrayIcon[0]);
>> 349:         }
> 
> Actually, the old code is more efficient than your new code.
> Per the spec https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/util/Vector.html#toArray(T%5B%5D)
> Returns an array containing all of the elements in this Vector in the correct order; the runtime type of the returned array is that of the specified array. If the Vector fits in the specified array, it is returned therein. Otherwise, a new array is allocated with the runtime type of the specified array and the size of this Vector.
> 
> So your new code allocates one more array than the old code.

It is not intuitive but the "zero version" is actually faster:

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PR: https://git.openjdk.java.net/jdk/pull/8850