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MapReduce >> mail # user >> what is the difference between the two packages "org.apache.hadoop.mapreduce" and "org.apache.hadoop.mapred"?


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Re: what is the difference between the two packages "org.apache.hadoop.mapreduce" and "org.apache.hadoop.mapred"?
org.apache.hadoop.mapreduce is a newer api. To avoid breaking backwards
compatibility the older api, org.apache.hadoop.mapred was preserved, and
the newer api was just given a new name.

Check out
http://www.slideshare.net/sh1mmer/upgrading-to-the-new-map-reduce-api

J

On Tue, 2011-04-26 at 20:17 +0800, 吕鹏 wrote:
> hi
>     when i read the source of mapred, i find there're a lot of classes
> with the same names between "org.apache.hadoop.mapreduce" and
> "org.apache.hadoop.mapred", such
> as "org.apache.hadoop.mapreduce.Counters" and
> "org.apache.hadoop.mapred.Counters", why does this happen? why not
> define only one Counters instead? what is the difference between the
> two packages "org.apache.hadoop.mapreduce" and
> "org.apache.hadoop.mapred"?
>
>
>     thx
>
>
>
>
> Lv Peng