Some animated GIF files fail to load, and either throw:

java.lang.ArrayIndexOutOfBoundsException: Index 4096 out of bounds for length 4096
        at javafx.graphics/com.sun.javafx.iio.gif.GIFImageLoader2$LZWDecoder.readString(GIFImageLoader2.java:385)
        at javafx.graphics/com.sun.javafx.iio.gif.GIFImageLoader2.decodeImage(GIFImageLoader2.java:167)
        at javafx.graphics/com.sun.javafx.iio.gif.GIFImageLoader2.load(GIFImageLoader2.java:232)
        at javafx.graphics/com.sun.javafx.iio.ImageStorage.loadAll(ImageStorage.java:374)
        at javafx.graphics/com.sun.javafx.iio.ImageStorage.loadAll(ImageStorage.java:271)
        at javafx.graphics/com.sun.javafx.tk.quantum.PrismImageLoader2.loadAll(PrismImageLoader2.java:142)
        at javafx.graphics/com.sun.javafx.tk.quantum.PrismImageLoader2.<init>(PrismImageLoader2.java:77)
        at javafx.graphics/com.sun.javafx.tk.quantum.PrismImageLoader2$AsyncImageLoader.processStream(PrismImageLoader2.java:252)
        at javafx.graphics/com.sun.javafx.tk.quantum.PrismImageLoader2$AsyncImageLoader.processStream(PrismImageLoader2.java:225)
        at javafx.graphics/com.sun.javafx.runtime.async.AbstractRemoteResource.call(AbstractRemoteResource.java:109)
        at javafx.graphics/com.sun.javafx.tk.quantum.PrismImageLoader2$AsyncImageLoader.access$001(PrismImageLoader2.java:225)
        at javafx.graphics/com.sun.javafx.tk.quantum.PrismImageLoader2$AsyncImageLoader.lambda$call$0(PrismImageLoader2.java:259)
 
or simply show one/two frames but fail to load the rest.

The attached test shows the latter.

In fact, with some debugging, it can be found that the same exception as above is happening but it is not thrown, because partially (as in just two frames) loaded gifs are allowed:

https://github.com/openjdk/jfx/blob/master/modules/javafx.graphics/src/main/java/com/sun/javafx/iio/ImageStorage.java#L376