In the reducer, the MapReduce API provides you with an iterator over Writable values. What does calling the next () method return?
A) It returns a reference to a different Writable object time.
B) It returns a reference to a Writable object from an object pool.
C) It returns a reference to the same Writable object each time, but populated with different data.
D) It returns a reference to a Writable object. The API leaves unspecified whether this is a reused object or a new object.
E) It returns a reference to the same Writable object if the next value is the same as the previous value, or a new Writable object otherwise.

Question

Quizplus · Accepted Answer

The next() method in the iterator returns a reference to the same Writable object each time, but it is populated with different data for each call.

In the Reducer, the MapReduce API Provides You with an Iterator