They are indeed. But it doesn't change the fact it's substantially limited beyond JASDF cover as a force w/o US umbrella.
Much more so than either French or British, which are "smaller".
Even if it fits with modus operandi - it shall not be an excuse when we compare force capabilities. Tradition won't replace nuclear power or fixed wing jets.
The JASDF are more than prepared, they have the encouragement of China's "ratcheted up" rhetoric and island building as motivation, to say they are only defensive has far more to do with doctrine, than it does with hardware. They are serious, and they are serious partners for the US, and they are very adept at "inter-operability"??
China takes them "very seriously", maybe you ought to look at why? They will have a much more "serious" partner in Trump, than they ever have for the last 8 years.