Parameterized constructor in servlet

Question

Can I declare parameterized constructor inside servlet which is only constructor ? If no then why ? JavaScript questions and answers, JavaScript questions pdf, JavaScript question bank, JavaScript questions and answers pdf, mcq on JavaScript pdf, JavaScript questions and solutions, JavaScript mcq Test , Interview JavaScript questions, JavaScript Questions for Interview, JavaScript MCQ (Multiple Choice Questions)

Answer 1

No. Servlet instances are created by the container via reflection, and they expect to find a public, no-arg constructor (the default constructor). To configure your servlet, use servlet parameters specified in the web.xml file. These are passed to your servlet's init() method. While it would be possible for a servlet container to choose a non-default constructor and coerce character strings to simple types and invoke the constructor reflectively, this isn't what the Servlet specification requires. Part of the reason may be historical; servlets were first specified long before dependency injection systems made this alternative widely practiced. However, such constructors would be fairly limited; it would be practical to pass arguments that can be created from a simple character string specified in the web.xml, but more useful objects—a DataSource, for example—would be awkward. It would be nice to have final member variables in a servlet though. The JSR formerly known as "WebBeans" (JSR 299, I think), will provide some standards for dependency injection support in Servlets. This might address some of the drawbacks in the current approach.