On Sun, 13 Jul 2025 09:12:27 GMT, Prasanta Sadhukhan <[email protected]>
wrote:
>> When trying to call 'icon.setImage(null);' where 'icon' is an instance of
>> ImageIcon, a null pointer exception is thrown at runtime.
>> The code tried to get the `id` for that image and instantiates
>> `MediaTracker` to associate the null image to that `id` and checks the
>> status of loading this null image, removes the null image from the tracker
>> and then tries to get the image width where it throws NPE as image is null.
>>
>> It's better to not go through all MediaTracker usage and bail out initially
>> itself for null image..
>
> Prasanta Sadhukhan has updated the pull request incrementally with two
> additional commits since the last revision:
>
> - Document NPE behaviour and update test and add class-level statement
> - Document NPE behaviour and update test and add class-level statement
src/java.desktop/share/classes/javax/swing/ImageIcon.java line 68:
> 66: * no exceptions will be thrown but the image will be 'effectively' null,
> 67: * as it will have no dimensions and never be drawn, and
> 68: * getImageLoadStatus() will report ERRORED.
ERRORED should be a link - I presume to MediaTracker.ERRORED
src/java.desktop/share/classes/javax/swing/ImageIcon.java line 215:
> 213: /**
> 214: * Creates an ImageIcon from the image.
> 215: * Passing {@code null} Image will result in {@code
> NullPointerException}.
"Passing" -> "Passing a"
src/java.desktop/share/classes/javax/swing/ImageIcon.java line 228:
> 226: * If the image has a "comment" property that is a string,
> 227: * then the string is used as the description of this icon.
> 228: * Passing {@code null} Image will result in {@code
> NullPointerException}.
"Passing" -> "Passing a"
src/java.desktop/share/classes/javax/swing/ImageIcon.java line 388:
> 386: public void setImage(Image image) {
> 387: this.image = image;
> 388: if (image == null) {
Umm. We had decided (in the end) to document the NPE.
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/25767#discussion_r2223374128
PR Review Comment: https://git.openjdk.org/jdk/pull/25767#discussion_r2223376459
PR Review Comment: https://git.openjdk.org/jdk/pull/25767#discussion_r2223376633
PR Review Comment: https://git.openjdk.org/jdk/pull/25767#discussion_r2223418097
