I found some topics, devoted to this issue (1, 2, 3).
And I would like to clarify the situation. The reason why I've created a forth topic about it is may I say that ServletConfig, GenericServlet and HttpServlet where formed on the basis of a Decorator design pattern? I've created a bried UML diagram of a Servlet API:
Ulf Dittmer wrote:See the paragraph "Easier initialization" in http://www.servlets.com/soapbox/servlet21.html for some explanation.
Thanks. After having read the paragraph I begin to understand why GenericServlet possesses overloaded "init" method (in version 2.5 the version of this method, that takes no arguments, has become empty). But the primary question was does all of this correspond to a certain design pattern.
Ulf Dittmer wrote:I don't see the Decorator pattern in this. It's not like there are other interfaces that could alternately or additionally be added to GenericServlet, or that there are other classes to which ServletConfig could be added.
Can you tell, what pattern is used, if any?