There are still sizable areas of protected land in Java, and in 2017 a warden took the below photo.
Now I am unsure about this picture but would be pleasantly pleased to be proved wrong.
If not, the Javan tiger is very similar to the Sumatran tiger. As such, with a recovery in the wild Sumatran population if a reserve is not suffering poaching, it would be possible to bring the tiger back to Java