下列代码中MapReduce怎样执行呢？

下列代码中MapReduce怎样执行呢？

public static void main(Stringlargs)throws Exception{ 
Configuration conf=new Configuration();
confset("dfs.defaultFS""hdfs://hadoop:9000") 
Job job=Job.getinstance(conf,"word count"); 
job.setJarByClass(WordCount.class);
job.setMapperClass(TokenizerMapper.class) 
job.setCombinerClass(IntSumReducer.class) 
job.setReducerClass(IntSumReducer.class; 
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(IntWritable.class);
FilelnputFormataddinputPath(job,newPath(args[0]); 
FileOutputFormat.setOutputPath(job,new Path(args[1])) 
System.exit(jobwaitForCompletion(true)?0:1);
}