You are trying to run a Hadoop operation. You issue your "hadoop jar" or "hdfs jar" command. You get one of these errors:
"Error: Could not find or load main class jar"
or this error
"Error: Could not find or load main class hadoop-streaming-2.8.1.jar"
What is wrong?
1. Use "hadoop..." instead of "hdfs".
2. Make sure you have the hadoop-streaming*.jar file. You could run this command to find it:
sudo find / -name hadoop-streaming-*.jar
If you cannot find it, you can download it from here.
3. Remember to put the full path after the "hadoop jar ". Here is an example:
hadoop jar /usr/local/hadoop/share/hadoop/tools/lib/hadoop-streaming-2.8.1.jar -file /home/hduser/mapper.py -mapper /home/hduser/mapper.py -file /home/hduser/reducer.py -reducer /home/hduser/reducer.py -input /user/hduser/contint/* -output /user/hduser/gooddir-output
Alternatively you could use "cd /to/the/path/with/hadoop-streaming-2.8.1.jar" (where 2.8.1 is just an example).