From JBuilder tutorial: When the servlet engine starts or when a servlet needs to respond to a request, the init() method is called by the servlet engine to tell a servlet that it is being placed into service. The servlet engine calls init() only once after instantiating the servlet.
From JBuilder tutorial: Servlets are used as: As part of a collaborative system, such as a messaging system, where several or more servlets are handling multiple requests concurrently.
Does it imply that servlet instances are servlets here? When instances and when threads are being used? How is it possible to engage instances of different servlet class? I.e. how does developer bind together engine, servlet and client application? Is servlet engine one per servlet?