RecordReader reads <key, value> pairs from an
InputSplit. Where key and value is-
key – the key to read data into
value – the value to read data into
RecordReader, typically, converts the byte-oriented view of the input, provided by the
InputSplit, and presents a record-oriented view for the
Reducer tasks for processing. It thus assumes the responsibility of processing record boundaries and presenting the tasks with keys and values.