Japanese API document was regenerated to reflect changes incorporated in Update 10.
http://java.sun.com/javase/ja/6/docs/ja/api/index.html

However, we recieved several reports through community claiming that some parts of doc went back to English.

http://java.sun.com/javase/ja/6/docs/ja/api/javax/lang/model/package-summary.html
http://java.sun.com/javase/ja/6/docs/ja/api/java/lang/StringBuffer.html
Whole correct docset of Japanese API was regenerated and published again.