Java MapReduce counting by date

Question

I\'m new to Hadoop, and i\'m trying to do a MapReduce program, to count the max first two occurrencise of lecters by date (grouped by month). So my input is of this kind :

Answer 1

The main problem is about the sign of the reduce method :

I was writing : public void reduce(Text key, Iterator values, Context context)

instead of

    public void reduce(Text key, Iterable values,

This is the reason why i obtain my Map output instead of my Reduce otuput