The JSF lifecycle is, in effect, for all Faces requests and responses including those that emanate from the AJAX-enabled components. Behind the scenes, JSF instantiates a special object, javax.faces.context.PartialViewContext for the AJAX requests and responses, and that is entered into the processing lifecycle. This context object contains the information that allows JSF to update the component model on the server-side. Based on the partial context, JSF decides whether to accomplish partial processing of the selected UI component and/or partial rendering of the UI components. Partial processing corresponds to the Apply-Requests-Values, Process-Validations, and Update-Model-Values phases of the lifecycle. Partial rendering refers to the Render-Response phase.
Partial request – response lifecycle for AJAX submissions
The preceding diagram encapsulates our understanding of the partial context for the AJAX request and response in the JSF lifecycle.