Dear Learner,

Hope you are doing well.

It seems the custom jars are not getting loaded into flume.

Please try with below solution

-edit flume.conf file and change TwitterAgent.sources.Twitter.type to 

TwitterAgent.sources.Twitter.type =  com.cloudera.flume.source.TwitterSource

also uncomment FLUME_CLASSPATH from flume-env.sh make sure you have necessary jars to run the flume.

Now go to /usr/lib/flume-ng/apache-flume-1.4.0-bin/bin and execute command
 ./flume-ng agent -c conf -f /usr/lib/flume-ng/apache-flume-1.4.0-bin/conf/flume.conf -n TwitterAgent

Please try this solution and let us know if you face any issue so we can help you out here.