Chapter 2. The Basics of a MapReduce Job

This chapter walks you through what is involved in a MapReduce job. You will be able to write and run simple stand-alone MapReduce programs by the end of the chapter.

The examples in this chapter assume the setup as described in Chapter 1. They should be explicitly run in a special local mode configuration for executing on a single machine, with no requirements for a running the Hadoop Core framework. This single machine (local) configuration is also ideal for debugging and for unit tests. The code for the examples is available from this book's details page at the Apress web site ( The downloadable code also includes a JAR file you can use to run the examples.

Let's start by examining ...

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