Chinese characters are converted into entities..

I am using JTidy to convert HTML with content of traditional Chinese characters (double bytes) to well-formed XML.
It seems that every single Chinese  character is converted to two XML entities like follows:

Input (Traditional Chinese):
中文測試

Output (XML entities):
¤¤¤å´ú¸Õ 

Is this an encoding problem? or is there any property of JTidy I can config to prevent JTidy converting double bytes characters to XML entities?

Many thanks,
Jason Chang