I'm far from convinced of the utility of algebraic effects, but if you like them, implementing them in Java (or any Java platform language) would be possible soon thanks to Project Loom [1]. The scoped (ALA multi-prompt) delimited continuations provided by Loom are intended for other uses, but they could also be used to implement algebraic effects.

[1] https://wiki.openjdk.java.net/display/loom/