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Why does GenericServlet implement ServletConfig

Alex Sharkoff
Ranch Hand

Joined: Apr 11, 2004
Posts: 209
Hi all,

I am just a bit confused with the following class structure.

Why does javax.servlet.GenericServlet implement javax.servlet.ServletConfig? It IS a servlet, not a servlet configuration. Seems like competely different responsibilities being assigned to one class.

Eg, it makes sense to have Employee class implement Person and Administrator interfaces (employee is a person, and has a role of administrator). But it does not make sense for the Employee class to implement EmployeeAddress interface.

In addition, GenericServlet inherits a Servlet#getServletConfig() method, which complicates the picture even more.

Would not the following piece of code get servlet config:

Why would one ever use GenericServlet#getServletConfig()? Does not it just return a reference to itself?

I'd say that the most appropriate relationship between servlet and servlet configuration should be *HAS*; servlet HAS a servlet configuration, then GenericServlet#getServletConfig() would make sense.

I'd greatly appreciate your thoughts on this matter.

[ October 24, 2004: Message edited by: Alex Sharkoff ]

Alex (SCJP 1.4, SCBCD 1.3, SCWCD 1.4, SCJD 1.4)
Nathaniel Stoddard
Ranch Hand

Joined: May 29, 2003
Posts: 1258
Ironically, only hippies (kidding) use GenericServlet (for what, who knows). HttpServlet, however, does not implement ServletConfig. I haven't yet met a person, even a hippy, who has used GenericServlet -- anybody?

Alex Sharkoff
Ranch Hand

Joined: Apr 11, 2004
Posts: 209
I've not met any admirers of GenericServlet either, everyone is only after HttpServlet beauties

HttpServlet extends GenericServlet, and therefore implicitly implements ServletConfig.

Gaurav Sahni
Ranch Hand

Joined: Sep 03, 2003
Posts: 56
Exactly ...
Since HTTPServlet extends the GenericServlet, and therefore implicitly implements ServletConfig.
Hence, the piece of code mentioned :

is a valid way of getting the servletConfig.

Another question would be, when a servlet is initialized, why do the container call the init(ServletConfig) method of HttpServlet, passing the servletConfig. The various configuration parameters should be available to the servlet automatically (since it has implemented the servletConfig.)

Can anybody clear the mud...

To know recursion, you must first know recursion...
I agree. Here's the link:
subject: Why does GenericServlet implement ServletConfig
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