What is Poll SCM?
Poll SCM periodically polls the SCM to check whether changes were made (i.e. new commits) and builds the project if new commits where pushed since the last build.
Configuration: Following schedule will poll the SCM every fifteen minutes and if it finds any commits, then it will automatically trigger a build in Jenkins
Schedule field follows the syntax of cron expression. Specifically, each line consists of 5 fields separated by TAB or whitespace:
MINUTE HOUR DAYOFTHEMONTH MONTH DAYOFWEEK
* specifies all valid values
Symbol H(for hashing) is used to produce even load on the system.