Saturday, November 2, 2013

Hadoop 2.x : jar file location for wordcount example

The Jar files  for Hadoop 2.x have moved location from Hadoop 1.x.  I found the following command

javac -classpath $HADOOP_HOME/share/hadoop/common/hadoop-common-2.2.0.jar:$HADOOP_HOME/share/hadoop/mapreduce/hadoop-mapreduce-client-core-2.2.0.jar:$HADOOP_HOME/share/hadoop/common/lib/commons-cli-1.2.jar -d wordcount_classes

will allow you to compile the standard wordcount example code.  You can see that the common files are in /share/hadoop/common/ and the mapreduce files are in /share/hadoop/mapreduce/.  Finally the common lib file are in /share/hadoop/common/lib

This post is in answer to this stackoverflow question:

(or set your classpath lke this

 export CLASSPATH=$HADOOP_HOME/share/hadoop/common/hadoop-common-2.2.0.jar:$HADOOP_HOME/share/hadoop/mapreduce/hadoop-mapreduce-client-core-2.2.0.jar:$HADOOP_HOME/share/hadoop/common/lib/commons-cli-1.2.jar

and compile like this:

javac -classpath $CLASSPATH -d myWordCountClasses