In the last post, we built a simple MapReduce job using C#. But Hadoop is a Java-based platform. So how is it we can execute a MapReduce job using a .NET language? The answer is Hadoop Streaming. In a nutshell, Hadoop Streaming is a capability that allows any executable to serve as the mapper and/or reducer in a MapReduce job. Through this capability, MapReduce exchanges data with the executable using its standard input and output, i.e. stdin and stdout.