The Chinese are super hackers?

From time to time one of our government sites gets hacked into. Most of the time that this happens, fingers get pointed to China. The most recent reported is they were trying to hack into information about our F-35 joint strike fighter. Supposedly there are reports that claim the Chinese military has made "steady progress" in developing online-warfare techniques in an attempt to compensate for an underdeveloped military. Of course the Chinese are saying they are opposed to Internet crimes and they would never do anything like that. Most of the time we are able to trace the hacks right to well known Chinese IP addresses, yet China says we keep making up these stories up.