JSP contains three life cycle methods namely jspInit( ), _jspService() and jspDestroy(). In these, jspInit() and jspDestroy() can be overridden and we cannot override _jspService().
The contents what we write in the JSP will go into _jspService() because we are implicitly implementing it. If we again try to override it explicitly, JSP compliler will giver error as ‘the method is already implemented and cannot override’. But in the case of other two methods we are not implementing it in the JSP. Therefore the JSP compiler will allow to override jspInit() and jspDestroy().
To show this difference _jspService() method is prefixed with ‘_’ by the JSP container and the other two methods jspInit() and jspDestroy() has no special prefixes.