I didn't find any other information about using dagger.producers to create execution graphs in parallel, so I have experimented myself.
I've copied the dagger 'simple' coffee example and changed it so that the Pump and Grinder are created in parallel.
The output now looks like this:
@Provide Heater
@Inject Thermosiphon
@Producing Pump..
@Producing Grinder..
done @Producing Grinder
done @Producing Pump
@Producing CoffeeMaker..
I had a few problems with the generated code not compiling due to some mismatch with Futures.transformAsync() and the maven compile still fails.
But I was able run it in Eclipse all the same.
You can find the code here: