Now let's go through some of the key APIs that you will be using while you program in MapReduce. First, let's understand the important packages that are part of Apache Hadoop MapReduce APIs and their capabilities:
Java API Packages |
Description |
org.apache.Hadoop.mapred |
Primarily provides interfaces for MapReduce, input/output formats, and job-related classes. This is an older API. |
org.apache.Hadoop.mapred.lib |
Contains libraries for Mapper, Reducer, partitioners, and so on. To be avoided—use mapreduce.lib. |
org.apache.Hadoop.mapred.pipes |
Job submitter-related classes. |
org.apache.Hadoop.mapred.tools |
Command-line tools associated with MapReduce. |
org.apache.Hadoop.mapred.uploader |
The org.apache.Hadoop.mapred.uploader package contains classes related to the MapReduce framework upload tool. |