Word count example

Many people who start to learn MapReduce development would have written Word count as their first program. Thus, it is sometimes known as the Hello World program of MapReduce. The basic idea of this program is to show how the MapReduce framework works. The pattern of Word count can be applied to use cases such as counting population by state, counting the total number of crime by state, finding total spending per person, and so on. Let's briefly discuss the word count program with a Mapper, Reducer, and combiner example.