Jetty provides capability to deploy an arbitrary context or web application by monitoring a configuration directory for changes to the deployment descriptors. If a descriptor is added to the directory, a new context will be deployed. If a descriptor is touched/updated then it's context will be stopped, reconfigured and redeployed. If a descriptor is removed, then it's context will be stopped and removed from the server. This capability is implemented via ContextDeployer mechanism.
The ContextDeployer may be used to (hot)deploy an arbitrary Context or Web Application with Jetty specific configuration. The deployment descriptors are in jetty xml format and define and configure individual contexts. If the scan interval is non-zero, the configuration directory is scanned at that interval (in seconds) for changes to the deployment descriptors.
To statically deploy only standard web applications at startup, use the WebApp Deployer. If the scan interval is zero, then the directory is only scanned at startup.