title: What is Keyword Context in Hadoop programming world?
body: <p>What exactly is this keyword <strong><em>Context</em></strong> in Hadoop MapReduce world in new API terms?</p>
  
  <p>Its extensively used to write output  pairs out of Maps and Reduce, however I am not sure if it can be used somewhere else and what's  exactly happening whenever I use context. Is it a Iterator with different name? </p>
  
  <p>What is relation between Class Mapper.Context, Class Reducer.Context and Job.Context?</p>
  
  <p>Can someone please explain this starting with Layman's terms and then going in detail. Not able understand much from Hadoop API documentations.</p>
  
  <p>Thanks for your time and help.</p>