Japan has responded by pointing out that China has nearly ten times as many troops (2.2 million versus 230,000), and a defense budget of over $30 billion. That's because many items Japan counts as defense costs, China does not (like R&D, some logistics and transportation items). Moreover, 45 percent of Japan's defense spending goes to salaries, while less than 20 percent of Chinese spending does. Although Japan does not like to admit it, it's high tech weapons cost a lot more than they should (because of low production runs and the use of highly paid Japanese, instead of offshore, workers). Another painful fact for the Japanese is that 5-10 percent of their defense budget goes to things like soundproofing the windows of homes near Japanese air bases. Japan is much more sensitive to relations with civilians living near military bases.
China is trying to make their people believe that Japan is a military threat to China. One way China does this is to point out that Japan's military spending is $42 billion a year, compared to $26 billion for China. Japan's more modern weapons are also highlighted, as well as Japan's decades of aggression in China, which only ended in 1945, when the United States nuked two Japanese cities.
Another vital point is that China has nukes, and Japan does not (although everyone acknowledges that Japan could equip itself with nuclear weapons in a year or so.) Chinese generals will admit to themselves, but not in public, that, man-for-man, Japanese troops are more effective. But not so much that Japan's armed might could be considered superior to Chinas. While Japan's defense budget has been shrinking every year since the late 1990s, China's has been growing. Thus any detailed discussion of the subject, like this one, is forbidden in the Chinese media, because it would clearly show that China's military power is growing, while Japan's is not.