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From "Y. Dong" <tq00...@gmail.com>
Subject MapReduce code location
Date Tue, 20 Aug 2013 10:06:55 GMT
Hi All, 

I'm a Mapreduce newbie, what I want to know is that,  say I have a mapper class:

public Class Map implements Mapper {
	
	public List A;
	public static List B; 

	public Map(){	//class constructor
		System.out.println("Im initializing");
	}

	@Override
	protected void map(………){
		System.out.println("Im inside a mapper");
		…….
	}

}

when I run this mapper on a multi-machine hadoop configuration, will hadoop instantiate
multiple instances of this class then transmit them to every remote machine?  So in a remote
machine will the map(…) method be able to access List A and List B locally from its own
memory? 
If yes, in the map method, what if I run System.out.println, will printed message be only
shown on 
the remote machine but not the machine I start the whole map reduce job?

Thanks. 

Eason
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