Term
| What is the difference between HTTP Post and HTTP Get? |
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Definition
| Get is essentially for getting data. Post may involve anything like storing,updating data, ordering a product or sending email. Get is encoded in the URL. Post is stored within the message body. Use get when details of the message have no effect. Use post when the details need to be hidden. Get also has limited data capacity whereas Post does not. |
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Term
| What is the life cycle of a Servlet? |
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Definition
| init(), service(), destroy() |
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Term
| What is the life cycle of a JSP? |
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Definition
| page translation, compilation, load , instantiate, jsp_init(), jsp_service(), jsp_destroy() |
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Term
| What is the difference between a Generic Servlet and an HTTP Servlet? |
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Definition
javax.servlet.Servlet is the central interface in the Servlet API. Every servlet class must implement this interface. It has 5 methods init(), service(), destroy(), getServletConfig() and getServletInfo()
a) Generic servlet implements the servlet interface. It is an abstract class that provides implementation for all methods except the service() method. We can extend this class and implement the service method to write any type of servlet.
b)HTTP Servlet extends the generic servlet . It provides support for the HTTP protocol it adds a new service() method with the signature service(HTTP request, HTTP response) For every HTTP method, there is corresponding method in the HTTPServlet class(doGet, doPost) |
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Term
| How do you preinitialize/preload a servlet? |
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Definition
| The servlet specification defines the element which can be defined in the deployment descriptor to make the web container load and initialize the servlet as soon as it starts up. |
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Term
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Definition
| ServletConfig is defined in the javax.servlet package. It provides 4 methods. getInitParameter(String),getInitParameters and getServletName. A servlet container takes the information specified in the deployment descriptor and wraps it into a ServletConfig object. This information can then be retrieved by the servlet at initialization. It is passed as a parameter to the init method init(javax.servlet.ServletConfig). |
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Term
| What are important tags in the ServletConfig? |
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Definition
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Term
| What is a servlet context? |
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Definition
| The servlet context is a window for a servlet to view its environment. Every web application has a single Servlet Context that is available to all resources in the application.It is used by the servlets to share data with each other. A servelt can use this information such as initialization parameters for the web application or servlet container version. This interface also provide utility methods for retrieving MIM type for a file, for retrieving shared resources and logging. |
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Term
| Name some important ServletContext tags |
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Definition
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Term
| How would you forward a request from a servlet to a JSP? |
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Definition
Using a request dispatcher.
RequestDispatcher dispatcher = httpServletRequest.getrequestDispatcher(url)
dispatcher.forward(httpServletRequest, httpServletResponse) |
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Term
| What is the difference between the RequestDispatcher.forward() and HttpServletResponse.SendRedirect()? |
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Definition
| forward() is handle completely on the server side.redirect sends a redirect message to the browser. Forward is transparent to the user. Redirect is not. Both javax.servletServletContext and javax.servlet.ServletRequest have the getRequestDispatcher(path) method. |
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Term
| What directory does the Deployment Descriptor reside(web.xml)? |
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Definition
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Term
| What does JSTL stand for? |
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Definition
| JSP Standard Template Library. |
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Term
| What are the various types of markup tags in a JSP |
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Definition
a) Directives (page, includes and tag lib)
b) Scripting elements
i <%!Declarations%> Declarations allow the developer to define various variables and methods in a page.
ii Scriptlets are lines of code that is executed each time a process request is made.
iii <%= Expression%> is an individual line of code.
c) comments
d)actions |
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Term
| What are the various scope is a JSP |
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Definition
| Page, Request,Session and Application |
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Term
| Name the implicit objects in JSP |
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Definition
Session -User Specific session data
Exception/Error - uncaught exception
Application Data shared by all pages in application.
Config- Servlet configuration data
Request- Request data including parameters
Response- Response data
Out- output stream for page
Page- Page servelet instance
Page Context -Context data for page execution |
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Term
| Name some action tags in JSP |
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Definition
a
b
c is used to generate browser specific HTML for specifying Java applets that rely on a JAVA plugin.
d) |
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Term
| What are directives? Can you name some directives in JSP. |
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Definition
Directives are used to convey special processing information about the page to the JSP container
a) <%@ page attri="val1"...%>
There are a list of attributes supported by the page directive. info, language, contextType, pageEncoding, extends, import, session, buffer, autoFulsh, isThreadSafe, isErrorPage
i isErrorPage is used to specify an alternate page to display if an uncaught error occurs.
ii. When isErrorPage is set to true, it indicates that the page is used as an error page.
b) Include Directive. <%@ include.. %>
c) Tag library directive <%@ taglib = url= "" prefix =""%> |
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Term
| What is the difference between static and dynamic include? |
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Definition
| The static include is the result of an include directive that occurs during page translation of the JSP life cycle. Dynamic include is the result of the standard action tag occuring in the body of the JSP. The two JSPs are loaded separately and are summed together at run time. |
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Term
| What are the different ways of handling a session? |
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Definition
| Cookies, Session and URL Rewriting |
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Term
| What is the difference between XML and HTML? |
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Definition
| XML describes the data. HTML displays the data. |
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Term
| How would you write a message back to the browser via a servlet? |
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Definition
PrintWriter out = response.getWriter();
out.println("text goes here") |
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