Its like Germany after world war I. They too did a huge turnaround with all the buildings and productions only to start another WW.
China has not forgeton the Japanese attack and they are rising to revenge that humiliation. They could very well attack Japan right now but they knew too well that Japs will receive American support. SO they are waiting and getting very strong in every field.
But if it has to attack Japs then it will first need to have a strong resoveirs of resources (labourers, Gold, metals). Thats where India comes into the picture. They will first get North lands of India before attacking Japs.
Ofcourse these are all worst case scenarios, but China is fast moving towards that.
