must override a superclass method

I just did an update from Mercurial, and I found one of the class having compilation error on one of the method.

XXXXX must override a superclass method

I do notice that method has an annotation called "@Override". A quick search, I found that's because my Eclipse's compilation level is set as 1.5.

Preferences->Java->Compiler
Make sure Compiler compliance level set as 1.6