RFR: 8255248: NullPointerException in JFXPanel due to race condition in HostContainer [v2]

[Andy Goryachev]

On Thu, 13 Nov 2025 03:09:21 GMT, Prasanta Sadhukhan <psadhukhan at openjdk.org> wrote:

>> modules/javafx.swing/src/main/java/javafx/embed/swing/JFXPanel.java line 212:
>> 
>>> 210: 
>>> 211:     private static void debug_println(String str) {
>>> 212:         if (DEBUG) {
>> 
>> I am sorry, I was not sufficiently clear.
>> This method does not need the conditional.  The conditionals are needed in **every** place that calls here.
>> In other words, we don't want to incur the string concatenation overhead if **DEBUG** is false.
>
> will that be too much overhead? We had used the same in jdk having DEBUG check in one place...but I will modify it for FX..

Then you might want to fix all these places in JDK!

The code you currently have now (after https://github.com/openjdk/jfx/pull/1968/commits/115001f6c92b587574c67624f0033cabaabe04d0 ) has minimum runtime overhead - basically a boolean check.

Anything else consumes more CPU and memory at runtime (we don't have a pre-processor in java thankfully), so `if(DEBUG) { debug_print(...); }` is the best, albeit a bit verbose option.

Event the modern logging facades incur more overhead with lambdas or formats, since one needs to actually enter the logging function to check whether the level/logger is enabled.  I mean `logger.debug("param {}", param);` or `logger.debug("param {}", () -> param());`

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PR Review Comment: https://git.openjdk.org/jfx/pull/1968#discussion_r2524388270