No, it clearly isn't. A Future, from Java 5's concurrency libs is close, but it doesn't offer the chaining construction -- it only offers get. The most similar-

No, it clearly isn't. A Future, from Java 5's concurrency libs is close, but it doesn't offer the chaining construction -- it only offers get. The most similar-looking code commonly used in Java is probably people who use Option (or Maybe for those who stole from Haskell instead) with a .transform. I don't think there's as much a need for it in Java because I'm less likely to want to write defensive code in that way outside of the browser. It looks like Play supplies F.Promise, which provides the same functionality with a different API. I do like the simplicity of the API in the JS promises. The something.transform(good, bad, progress) is very easy to understand from the start.