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Mapreduce Interview Questions and Answers Part – 4 4

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In this post, we will discuss about another 50 Mapreduce Interview Questions and Answers for experienced mapreduce developers. Mapreduce Interview Questions and Answers for experienced 1. What are the methods in the Mapper class and order of their invocation?


run(Context context) 
{
 setup(context);
 while (context.nextKeyValue()) 
 {
 map(context.getCurrentKey(), context.getCurrentValue(), context);
 }
 cleanup(context);
}

setup(Context context)
map(Writable key, Writable value, Context context)
cleanup(Context context)

run(Context context)

{

setup(context);

while (context.nextKeyValue())

{

map(context.getCurrentKey(), context.getCurrentValue(), context);

}

cleanup(context);

}

setup(Context context)

map(Writable key, Writable value, Context context)

cleanup(Context context)

The Mapper contains the run() method, which call its own setup() method only once, it also call a map() method for each input and finally calls it cleanup() method. We can […]

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