Why Servlets having Init() even though its having constructors

Question

Hi friends , i ve one doubt,
in servlets all initilization part can be handled by Iinit() method,
my qn is each servlet is singleton oriented i.e, each has only one instance, it means only one time constructor will called, and init() also called only once, so instead of init() we can use constructor, in this case why sun people provide us init() method,
please give me soln.

Answer 1

-nevermind-
I've found something interesting in Google:
http://www.unix.org.ua/orelly/java-ent/servlet/ch03_03.htm
The init() method is typically used to perform servlet initialization--creating or loading objects that are used by the servlet in the handling of its requests. Why not use a constructor instead? Well, in JDK 1.0 (for which servlets were originally written), constructors for dynamically loaded Java classes (such as servlets) couldn't accept arguments. So, in order to provide a new servlet any information about itself and its environment, a server had to call a servlet's init() method and pass along an object that implements the ServletConfig interface. Also, Java doesn't allow interfaces to declare constructors. This means that the javax.servlet.Servlet interface cannot declare a constructor that accepts a ServletConfig parameter. It has to declare another method, like init(). It's still possible, of course, for you to define constructors for your servlets, but in the constructor you don't have access to the ServletConfig object or the ability to throw a ServletException.