China forcefully protested the recent publication of a U.S. Department of Defense report on Chinese military power. The Pentagon study pointed out that Chinese defense spending had doubled in the last decade, and that even this number was deceptive. China, like all other communist nations, regularly hides most of its defense spending elsewhere. Thus while the current official Chinese defense budget is about $59 billion, the actual spending is about twice that The U.S. report pointed out that the Chinese have no military threats along its borders, and the only justification for a major military buildup is to provide sufficient force to take over Taiwan quickly (before American forces could intervene), or impose its will on various offshore territorial disputes.
China insists that its military spending is purely for defensive purposes. What China does not comment on is the two decades of officially sanctioned media activity inside China, wherein the United States is portrayed as the opponent in a future war. The books, articles and films all make this future war sound inevitable. China does not allow, officially at least, this stuff to be translated. But Westerners can obtain it, and some has been translated. Once you go over this material, China's defense spending, and their recent protests about it, make sense. The Chinese leadership, a bunch of Communist Party politicians, are desperate to keep their police state going. Creating a credible external enemy, and mobilizing nationalistic fervor, is a classic way of retaining power.
China is trying to modernize their military, with particular emphasis on technologies and techniques that will avoid fighting American strengths head on. Again, this is a major discussion point in Chinese military journals. It's no secret, if you can read Chinese. Thus China's reaction to the Department of Defense report is based on that idea that anything published on the subject in Chinese doesn't count. Since few Western journalists can read Chinese, the Chinese strategy will probably work. It has so far.