Not the parent, but presumably it would allow for fancy monad stuff like Scala's Cats Effects[0] and Zio[1] which can make async programming easier to follow without having to introduce async/await

[0]: https://typelevel.org/cats-effect/ [1]: https://zio.dev

Not specifically for Java but I have found myself wanting do-notation in non-functional languages so that I can basically write a very expressive library while also forcing users of that library to go down my road i.e. I hacked around it in the end as I didn't have a do-like abstraction but I had (in-effect, it wasn't quite a DSL) written a DSL that represented certain constructs just fine using operator overloading, but you can't overload control flow. Therefore building the notions I wanted to in code was very painful without some kind of (equivalent notion to) do-notation.

There are lots of places where it can help, but to give one example consider the Java 8 Optional type.

It’s great for avoiding nulls, but you get excessive nesting with many isPresent checks. Do notation can fix this.

The language even provides a bind function, but no reasonable way to use it!