This question is related to my question on existing coroutine implementations in Java. If, as I suspect, it turns out that there is no full implementation of coroutines cur
I'd suggest to look at Kotlin coroutines on JVM. It falls into a different category, though. There is no byte-code manipulation involved and it works on Android, too. However, you will have to write your coroutines in Kotlin. The upside is that Kotlin is designed for interoperability with Java in mind, so you can still continue to use all your Java libraries and freely combine Kotlin and Java code in the same project, even putting them side-by-side in the same directories and packages.
This Guide to kotlinx.coroutines provides many more examples, while the coroutines design document explains all the motivation, use-cases and implementation details.