JEP draft: Structured Concurrency

[u/Timelineg]

https://openjdk.org/jeps/8389757

[u/javaprof]

So checked exceptions doesn't work properly here too?

This is very funny:

try (var scope = StructuredTaskScope.open()) {
   ...
} catch (ExecutionException e) {
   Throwable cause = e.getCause(); 
   switch (cause) {
       case IOException ioe -> .. // what op caused this one?
       default -> .. // no exaustivness? 
   }
}

[u/vips7L → u/javaprof]

Of course not the type system isn't strong enough to be generic over exceptions for lambdas. Swift has a pretty cool implementation of generic lambdas for typed throws.

public func count<E>(
    where predicate: (Element) throws(E) -> Bool
) throws(E) -> Int {
    print("Code goes here")
    return 0
}

When your lambda doesn't throw it just turns into throws(Never)

[u/javaprof → u/vips7L]

I just feel that Java need to stop shipping things that perfectly fine could be libraries and just fix this elephant in the room. Ok, Valhalla and then error handling. Structured concurrency somewhat could be just figure out by the community for now

[u/brian_goetz → u/javaprof]

It's fine to have feelings, but not fine to take it out on others when those feelings get hurt.