Deep diving into MapReduce APIs

Let's start looking at different types of data structures and classes that you will be using while writing MapReduce programs. We will be looking data structures of input and output to MapReduce, and different classes that you can use for Mapper, Combiner, Shuffle, and Reducer.

Configuring MapReduce jobs

Usually, when you write programs in MapReduce, you start with configuration APIs first. In our programs that we have run in previous chapters, the following code represents the configuration part:

The Configuration class (part of the org.apache.Hadoop.conf package) provides access to different configuration parameters. The API reads properties from the supplied file. The configuration...