StackOverflow link -
http://stackoverflow.com/questions/11784729/hadoop-java-lang-classcastexception-org-apache-hadoop-io-longwritable-cannot
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My program looks like
public class TopKRecord extends Configured implements Tool {
public static class MapClass extends Mapper<Text, Text, Text, Text> {
public void map(Text key, Text value, Context context) throws
IOException, InterruptedException {
// your map code goes here
String[] fields = value.toString().split(",");
String year = fields[1];
String claims = fields[8];
if (claims.length() > 0 && (!claims.startsWith("\""))) {
context.write(new Text(year.toString()), new
Text(claims.toString()));
}
}
}
public int run(String args[]) throws Exception {
Job job = new Job();
job.setJarByClass(TopKRecord.class);
job.setMapperClass(MapClass.class);
FileInputFormat.setInputPaths(job, new Path(args[0]));
FileOutputFormat.setOutputPath(job, new Path(args[1]));
job.setJobName("TopKRecord");
job.setMapOutputValueClass(Text.class);
job.setNumReduceTasks(0);
boolean success = job.waitForCompletion(true);
return success ? 0 : 1;
}
public static void main(String args[]) throws Exception {
int ret = ToolRunner.run(new TopKRecord(), args);
System.exit(ret);
}
}
The data looks like
"PATENT","GYEAR","GDATE","APPYEAR","COUNTRY","POSTATE","ASSIGNEE","ASSCODE","CLAIMS","NCLASS","CAT","SUBCAT","CMADE","CRECEIVE","RATIOCIT","GENERAL","ORIGINAL","FWDAPLAG","BCKGTLAG","SELFCTUB","SELFCTLB","SECDUPBD","SECDLWBD"
3070801,1963,1096,,"BE","",,1,,269,6,69,,1,,0,,,,,,,
3070802,1963,1096,,"US","TX",,1,,2,6,63,,0,,,,,,,,,
3070803,1963,1096,,"US","IL",,1,,2,6,63,,9,,0.3704,,,,,,,
3070804,1963,1096,,"US","OH",,1,,2,6,63,,3,,0.6667,,,,,,,
On running this program I see the following on console
12/08/02 12:43:34 INFO mapred.JobClient: Task Id :
attempt_201208021025_0007_m_000000_0, Status : FAILED
java.lang.ClassCastException: org.apache.hadoop.io.LongWritable cannot
be cast to org.apache.hadoop.io.Text
at com.hadoop.programs.TopKRecord$MapClass.map(TopKRecord.java:26)
at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:144)
at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:764)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:370)
at org.apache.hadoop.mapred.Child$4.run(Child.java:255)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:396)
at
org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1121)
at org.apache.hadoop.mapred.Child.main(Child.java:249)
I believe that the Class Types are mapped correctly, Class
Mapper<http://hadoop.apache.org/common/docs/current/api/org/apache/hadoop/mapreduce/Mapper.html>
,
Please let me know what is that I am doing wrong here?
Thank you
+ Harit Himanshu
