We availed of the services of JogjakartaDriver.com during our trip to Central Java in Indonesia last month. I found them on Tripadvisor, where they have good reviews that appear legit.
I emailed them at jogjakartadriver@yahoo.com and their main man, Danar, replied in less than 24 hours. I also inquired with two other car hire services other than JogjakartaDriver.com, and their rates and inclusions were pretty much the same. I ultimately chose to go with Danar because he made the most courteous response, in the best English, that addressed all of my questions.
The vehicle we got for the duration of our four-day tour was an air-conditioned Toyota Avanza, which had ample passenger space for the three of us. Our driver was Yus, and he was a very good and punctual driver. His English was not as good as Danar’s, but we had insightful conversations during our long drives and we understood each other just fine.

All in all, we had a great time with Yus. If you’re looking for a tour driver in Central Java, we don’t hesitate to recommend him and JogjakartaDriver.com.