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What are types of servlet?
Http servlet and Generic servlet
Generic Servlet and HTTP Servlet?
javax.servlet.GenericServletSignature: public abstract class GenericServlet extends java.lang.Object implements Servlet, ServletConfig, java.io.SerializableGenericServlet defines a generic, protocol-independent servlet.GenericServlet gives a blueprint and makes writing servlet easier.GenericServlet provides simple versions of the lifecycle methods init and destroy and of the methods in the ServletConfig interface.GenericServlet implements the log method, declared in the ServletContext interface.To write a generic servlet, it is sufficient to override the abstract service method.javax.servlet.http.HttpServletSignature: public abstract class HttpServlet extends GenericServlet implements java.io.SerializableHttpServlet defines a HTTP protocol specific servlet.HttpServlet gives a blueprint for Http servlet and makes writing them easier.HttpServlet extends the GenericServlet and hence inherits the properties GenericServlet.
Difference between HTTP servlet and Generic servlet?
The difference is that a GenericServlet has no defined protocol (it is "generic"), while HttpServler uses the HTTP protocol. HttpServlet is a subclass of GenericServlet with the purpose of creating a servlet for a web site.
Can insert javascript coding in servlet?
No. Javascript code can be present inside a JSP but not inside a servlet. A Servlet is a pure java class.
What class is a new servlet usually inherited?
The servlet class created in web applications usually extend the javax.servlet.HttpServlet class. The HttpServlet extends the javax.servlet.GenericServlet. These classes contain the basic features that are required to run a web application.
What is servlet mapping?
A Servlet Mapping is a directive in the web.xml that tells the Servlet Container which class to use when a particular Servlet is called. A Servlet is a class within your Java Web Application. Let's say you have a servlet called MyServlet in the com.example.servlet package. You would need to have a Servlet Mapping pointing the path "/MyServlet" to the "com.example.servlet.MyServlet" class. Without the servlet mapping, you would not be able to invoke your servlet because the Servlet container would not know where it is. JSPs are different - they do not need mappings like this. JSPs exist within the WebRoot of the application, so they are always available. Servlets exist in the WEB-INF\Classes directory once your application is deployed.
What is javax servlet?
A Servlet is a Java programming language class used to extend the capabilities of a server. Although servlets can respond to any types of requests, they are commonly used to extend the applications hosted by web serversA Servlet is a Java-based server-side web technology.The javax.servlet package contains a number of classes and interfaces that describe and define the contracts between a servlet class and the runtime environment provided for an instance of such a class by a conforming servlet container.
Which class a servlet use to receive a request from a client?
HttpServletRequest
What does generic class mean in java?
Generic
Why servlet has no constructor?
Because it is not a regular Java Class that is executed by a JVM. It is a special Java class that is executed by the Web Container which initializes and loads the servlet and the service methods get executed everytime it receives a request.
How do you get servlet context instance to servlet?
You can get the ServletContext instance in a servlet by using the getServletContext() method provided by the HttpServlet class, which is the base class for servlets. This method returns the ServletContext object associated with the servlet. For example: ServletContext context = getServletContext();
What is difference between single threaded servlet and multi threaded servlet?
The single thread model means that your servlet would not be multi-threaded. If there are two concurrent requests to your servlet then 2 instances of your servlet will be created to process these 2 requests. You can implement the single thread model by implementing the SingleThreadModel interface in your class. This is just a marker interface and does not have any methods. The multi threaded model means that your servlet would be multi-threaded and only one instance would exist. Multiple concurrent requests would be served by the same instance but in different threads. You can implement the multi threaded model by not implementing the SingleThreadModel interface in your servlet class.
