Classic, apart from its more generalized meaning of something old, tested and having certain artistic qualities, also has a more specific meaning when used to translate the Chinese Ching.
There are many works of Chinese literature, some dating back to before the Han Dynasty, but only 5 of those, the Confucian Canon can properly be referred to with the title of Ching, or classic. Two of these are the I Ching, or Book of Changes and the Shih Ching, or Book of Songs. Not even the Lun Yu, or Conversations of Confucius is referred to as a classic in the strictest sense.
And although I often use the phrase myself, no novel written in Chinese is a "classic novel", since novels are trash, and relativly newfangled, since the earliest Chinese novel, Outlaws of the Marsh, was written 800 years ago, barely yesterday.