Hi, thank you for the reply and the suggestion. In my case it was the best solution to have both threads run concurrently, and let A2 consume what is produced by A1 on the fly. A1 runs slower than A2, so sometimes A2 had to wait for A1. But apparently it's not possible to wait() in an AsyncTask. I'll change my architecture, but still I like the first solution better. As I wrote in another forum as well, until tonight I used to like the idea of AsyncTask. I simply don't understand why the creators of Android don't make such handy ideas more generic.