First of all, be sure you have read the Getting Started chapter.
A configuration is a
freemarker.template.Configuration object that
stores your common (global, application level) settings and defines
variables that you want to be available in all templates (so called
shared variables). Also, it deals with the creation and caching of
Template instances.
An application typically uses only a single shared
Configuration instance. More precisely, typically
you have one Configuration instance per
independently developed component that internally uses FreeMarker, so
they can be configured independently of each other. For example, your
e-mail sender component and your report generator component (service)
probably want to use their own Configuration-s, as
their needs differ.
As the behavior of templates depends on the configuration
settings, each Template instance has an associated
Configuration instance. If you obtain the
Template instances with
Configuration.getTemplate, the associated
Configuration instance will be the one whose
getTemplate method was called. If you create the
Template instances directly with the
Template constructor, the
Configuration should be specified as constructor
parameter.