If input directory is empty, then no mappers or Reducer will run?

[#1]

If input directory is empty, then no mappers or Reducer will run?

[#2]

As a number of mappers depend upon the number of InputSplits , as no data no input splits hence no mappers. Without any mapper, a number of the reducer is also 0.

If we try to run map/reduce job on Hadoop cluster without specifying any input file it will throw following exception: java.io.IOException: No input paths specified in job.