Basics info for all the tools
Jenkins--> Build Periodically --> here we use chron expression , as per the mentioed time job get trigger , even though their is not any new chnges in SCM.(which is intgrated with jenkins). but the build get trigger as per the mentioned time.
Poll SCM--> it is same as build periodically but job gets trigger when their is any changes in SCM. If the changes is as it is then the job is not getting trigger.
java -jar jenkins-cli.jar -auth u:p -s http://localhost:8080/ build "job_name_full_path" -p key=value -p key=value -p key=value -s