1. China does not have a history of conquests. It has mostly tried to remain isolated within. With a history and civilization of millenniums, China is a mature nation with very smart leaders and disciplined population.
2. Except in a section of Indian media and motivated Western media, there is no indication that China ever considered the possibility of war with India. In all her appreciations China has never considered India as an adversary or competitor in any field. The anti-China hype created is obviously the work of Western arms peddlers who look for more opportunities to push sales.
3. Taiwan is taken by China as a part of the nation. Among outside investors in PRC, Taiwan leads. There are many areas where the two cooperate. They have huge trade between themselves. China gets really upset with anyone viewing Taiwan as a separate sovereign entity.
4. Japan, S Korea and the Philippines have continued to remain occupied by US troops since WW II /Korean War. Not unrealistically China sees these as US vassals where US has deployed its front line against China. China sees her historical foe Japan as the real enemy in Asia. With a fast expanding military and the best air force in Asia, Japan is the nation that China has on its cross hair.
5. Naah, China does not consider India enough of a threat to launch war on. The border issues are not life and death issues. China also sees India much embroiled in internal issues ranging from J&K, Red Corridor to NE. India is too busy and focused on industrial/economic developments. Neither India nor China is really interested in starting a conflict that the West may be hoping.