Servlets Life cycle methods:init(),service(),destroy(). If I can use those methods in any Servlet web application programming it is internally servlet container treated as _jspservice() and this method generating code on Java with normal basic code.
Any methods are not be overriden by end users are typically written starting with '-'. _jspService method is not also be overriden by end users.Container invoke this method for each request, passing the request and response object.