Google api for trip planning inside my app?

Currently in my app i got a MapView, couple of Geopoints in my map, and the current destination of the user via GPS.

My question is, how can i use Google's route planning API... if is there any?
So i just want to plan routes to the Geopoints from the user's destination.

Any example or tutorial for this ? I only found one but thats not in java.

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