Why does a servlet has init method

[Steve Grant]

Hi,
This question is on servlet.
Why cant we use constructor of a servlet class as a initializer
for that servlet instead of init() method.
Why we need init method when we can use non-argument
constructor as initializer for that servlet.
I know that init method has something to do with the life cycle of
servlet. But still cant we use constructor instead of init method.

Thx ,
Steve

[William Brogden]

See this recent discussion for exhaustive discussion.
Bill

[Malli Raman]

1. I think it is the way you can seperate the initialization logic with basic default construction to make easy for the reusability.

2. The container will always instantiate the servlet with the default constructor and you won't get the servlet config object in the default constructor method, which is used to get the servlet configuration details, servletContext details.

[M. Gagnon]

I think Malli's answer is a good one. When you have the init() method you can do things like the following:

MyClassWithLotsOfStaticMethods.setDbConnStr(getServletContext().getInitParameter("dbconn"));

With the above I can simply change the database connection string I need in the deployment descriptor when I change from one environment to another with no need to recompile anything. Way cool!