Now I disagree with Ron's assertion that continuations compose better than monads. Here's why:

All monads can be expressed in terms of the continuation monad. As the name suggests this is just a monadic encoding of continuations. (See https://www.schoolofhaskell.com/school/to-infinity-and-beyon...).

If your language has continuations built-in then all programs are effectively running in some "ambient" monad that can express all other monads. Just like if you have exceptions you're effectively running within an error-handling monad.

So essentially rather than writing `F A` (or `F[A]` or `F<A>` or whatever syntax your language supports) to represent effectful programs all programs are implicitly running within such an effect type.

In a Haskell context, since continuations are typically implemented as a monadic value, the statement would be more or less nonsensical. But I don't think that would be the context in question.

Edit: noelwelsh speaks of another level of composition than I was, where one is trying to take, say, State and STM and create a new monadic value that does both those things. The analysis given there is correct as well. My point here is more syntactic and basic functioning, in that even if you pick a single monadic value type to stick with, it's not going to play well in Java anyhow. So, in conclusion, generalized monad-type code in Java is just comprehensively not really possible. Continuations, or what are being called that in modern times, however, fit into Java-type languages, as proved by several very similar languages that have had them for many years, and they work fine.