Question

I have managed to run hadoop examples grep, wordcount… however I am finding some hard time trying to get my own code to run…
This is what I have done;

I copied the grep code from the examples jar and made my own changes to it. I compiled it using the command javac; and I could see in the folder I specified the hierarchy “org/apache/hadoop/examples/filename.class “

I then packed it (the folder) into a jar; in it now is org/apache/…..
Now when I ran the command “bin/hadoop jar folder.jar filename input output ”
I keep on getting this error:

Exception in thread "main" java.lang.ClassNotFoundException:.... 

any ideas? or guidance?

Answer 1

Check you are running the command with the fully qualified class name of grep:

hadoop jar folder.jar org.apache.hadoop.examples.Grep ..other_args..