reducer gets values with empty attributes

[alxsss]

Hello,

I try to write mapreduce program in hadoop -1.0.4. using mapred libs. I have a 
map function which gets
keys and creates a different object with a few attributes like id and etc and 
passes it to reducer function using

 output.collect(key, value);

Reducer gets keys, but values  has empty  fields (like id and etc) , although 
map correctly assigns these fields to each value.

Any ideas why this happens?

Thanks.
Alex.