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Posted to mapreduce-user@hadoop.apache.org by 吕鹏 <lv...@gmail.com> on 2011/04/26 14:17:15 UTC
what is the difference between the two packages "org.apache.hadoop.mapreduce"
and "org.apache.hadoop.mapred"?
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
Re: what is the difference between the two packages
"org.apache.hadoop.mapreduce" and "org.apache.hadoop.mapred"?
Posted by Jeremy Lewi <je...@lewi.us>.
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