I read the Java article in BP twice. It was interesting and the author knows his Java "stuff." I especially liked the true picture of a newbie's egg incubation efforts. As an anecdotal piece, it was nice. And it left me feeling there is more to say on the issue. Here it is, long-winded as usual.
I wouldn't assume anything from that one article. There was no evidence to support the claims that Javas are better than others at foraging, since that seems to be the key topic here. His personal experience, in his one place on earth, is not the end all on the matter. Too, he offered no documented data to support his claims of lessened feed requirements.
If you read the article, you'd learn that the author is blessed with the ability to roam his birds on 21 acres of virgin hardwoods. They probably do not eat thesmelves out of the grubs, worms and insects under such conditions that are the main protein constituents in that environment. He doesn't have a large flock, either and so I can see why he doesnt offer them supplemental feed quantities, aside from scratch.
On the other hand, keep your Javas in confinement on the normal few acres, with the usual lifeless moonscape they create and I suspect your outcome would be vastly different than his.
As I see it, if you like black birds with beetle green sheen, you now have two choices, as has been noted: Austrolorps and Javas. Keep in mind, I aint knocking the author or his efforts. He is persistent, for sure!
But again, expecting birds to forage for their food means there has to be some and you must know that it is both adequate and sufficient for their needs. If you live on 21 acres of virgin, mountaintop hardwoods, then you might be able to duplicate his results. If NOT, you'll porbably need to devise another strategy or come up wanting.
Chickens are like wine, in that the infinite descriptors used to describe either one are HIGHLY subjective. What one person likes or finds notable may not jibe with your differing experience, taste or conditions. I know we like to get all glassy-eyed over the seemingly endless variety of chickens, but it's not the chickens, folks. The bird, in and of itself, is almost self-regulating and a good poultryperson can do well with most any breed.
The Truth here is the same as it always has been. A tad boring, perhaps, as the Truth is rarely interesting or colorful. But, it is what it is:
Success with chickens, no matter the breed, invariably lies in their proper management.