It is free and open source and safe for commercial applications as well as non-commercial ones. You are free to customize it as you wish, or even extract its source code to make your own version.
Android is getting more powerful every year. If you think there is anything interesting on today's market, you will probably be surprised to see what's happening in the next weeks and next months. That being said, this article will leave you out of breath, and you will give you almost 50e0806aeb gler