The as-yet-unnamed aircraft carrier was constructed a year ago, and went out to sea on Sunday for sea trials. Aircraft carriers take years to build and to put into service, but they have lifespans of 30 - 50 years.
China bought its first aircraft carrier--the Soviet-era Admiral Kuznetsov--from Ukraine a few years ago to copy its technology and to use it to learn the basics of carrier operations. They know its limitations and wouldn't send it into combat unless they were very desperate.
China's second carrier was manufactured indigenously, and is slightly larger than the first. It incorporates lessons learned, as well as whatever knowledge they've acquired about U.S. aircraft carriers through espionage. I think this milestone indicates that China has surpassed Russia in terms of shipbuilding technology and competence. Nevertheless, this carrier is much smaller and lower-tech than American aircraft carriers.
China has plans to build a third carrier and in fact may have already started. It's unclear whether it will be an iterative improvement upon the second carrier, or if they will take more risks and try to close the gap with their U.S. counterparts.