A recursive result-bearing Java.Util.Concurrent.ForkJoinTask.

For a classic example, here is a task computing Fibonacci numbers: However, besides being a dumb way to compute Fibonacci functions (there is a simple fast linear algorithm that you'd use in practice), this is likely to perform poorly because the smallest subtasks are too small to be worthwhile splitting up. Instead, as is the case for nearly all fork/join applications, you'd pick some minimum granularity size (for example 10 here) for which you always sequentially solve rather than subdividing.

[Android Documentation]