Importing gas turbo from US or UK,carronade from Italia,radar and VLS from US and then building a hull to fix them.This is just the so-called Japanese high tech.
If war begin,we can keep on producing more and more warships,but Japan is not able to build their own ship without imported elements.
BTW,while Japan lauch a DDG,we lauch 5 DDGs.By 2020,the tonnage of PLAN will be at least 4 times of JMSDF.The next gen PLAN warships will use the most advanced technology and they will be very huge and powerful,just like 055 DDG,054B FFG,001A & 002 AC,etc.PLAN will have the capacity to challenge US navy's 7th fleet in just one decade.