On Fri, 20 Jun 2025 03:51:16 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 one
> additional commit since the last revision:
>
> Remove resetting description from constructor as it is already null
src/java.desktop/share/classes/javax/swing/ImageIcon.java line 233:
> 231: Object o = image.getProperty("comment", imageObserver);
> 232: if (o instanceof String) {
> 233: description = (String) o;
To address [Phil's
comment](https://github.com/openjdk/jdk/pull/25767/files#r2155610976):
> This is wasted work if the app calls ImageIcon(Image, String) because that
> promptly over-writes whatever was obtained via this code.
If we're going to change the constructors, to avoid *this wasted work* when
`ImageIcon(Image, String)` constructor is called, I suggest moving the work
into `ImageIcon(Image, String)` and implement `ImageIcon` like this:
public ImageIcon (Image image) {
String description = null;
if (image != null) {
Object o = image.getProperty("comment", null);
if (o instanceof String) {
description = (String) o;
}
}
this(image, description);
It is allowed in JDK 22 and later.
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/25767#discussion_r2159249820
