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kotlinlang

also there is a feature request to simplify such code like your
<https://github.com/Kotlin/kotlinx.coroutines/issues/171>

yes, but you can write simple version yourself until such extension not available

also this can be useful
<https://github.com/Kotlin/kotlinx.coroutines/issues/172>

I want to use Kotlin classes inside java spring app. Where a lot of call of other actions inside another action of controller. There are many blocking call instead of async

How do u think, it is possible to include a little bit of kotlin into biggest java app? or will be better use  Future/Promise?

I think it’s complicated question, but I don’t see any problems to try.
Coroutines allow to write much more clear async code at least, also, you can rewrite blocking calls to non-blocking and probably improve scalability.

but imo coroutines much better than Future/Promise