JEE Flashcards
Describe a servlet
A servlet is a small java program that runs inside a web server
Describe GenericServlet
GenericServlet is a protocol-indepent Servlet which contains the service method, with other helper methods that log and gather information about the application and servlet configuration
Describe the Servlet interface
The Servlet is a simple interface that contains methods for initializing and destroying the Servlet, as well as servicing requests
Describe two ways in which request parameters come
- Query parameters, also known as URI parameters e.g. GET /index.jsp?productId = 45845545&category=Books
- or multipart/form data
e.g POST /index.jsp?returnTo=product page
Host : www.example.com
Content-Length: 48
Content-type: application/x-www-form-urlencoded
doDelete() is responsible for _
doDelete() is responsible for deleting the resource at the specified URL
doGet() is responsible for _
doGet() is responsible for retrieving the resource at the specified URL
doHead() is responsible for _
doHead() is responsible for retrieving the resource at the specified URL, but only headers are returned
doOptions() returns _
doOptions() returns which HTTP methods are allowed
doPost() is typically used for _
doPost() is typically used for web form submission
doPut() _
doPut() stores the supplied entity at the URL
doTrace() is used for _
doTrace() is responsible for diagnostic purposes
For responding to _ requests, the javax.servlet.http.HttpServlet _ GenericServlet, and implements the _ method to accept only HTTP requests
For responding to HTTP-specific requests, the javax.servlet.http.HttpServlet extends GenericServlet, and implements the service method to accept only HTTP request
How do you instruct tomcat to start the servlet immediately when the web application starts
you do this by configuring the web.xml with the following:
1
The _ interface is an extension of ServletRequest that provides additional _ information about a received request.
The HttpServletRequest interface is an extension of ServletRequest that provides additional HTTP protocol-specific information about a received request. It specifies dozens of methods that can be used to obtain details about an HTTP request, eg HttpServletRequest request.getContextPath();
True or False, as of Java EE7, the only Servlet protocol currently supported is HTTP
True
True or False, every servlet implements the javax.servlet.Servlet interface?
true
True or False, in almost all cases, Servlet inherit from java.servlet.GenericServlet
True
True or False, you should always use the destroy method to clean up resources held up by your Servlet between requests
True
What are the responsibilities of a servlet
A servlet receives and responds to requests from web clients, usually across HTTP
what does the deployment descriptor do?
the deployment descriptor instructs the web container how the application should be deployed
What is the most important capability of the HttpServletRequest?
The most important capability of the HttpServletRequest is to retrieve parameters passed by the client
When is the destroy method called?
The destroy method is called when the web application is stopped or undeployed, or when the web container shuts down
When is the init method called?
The init method is called when the Servlet starts:
- if the servlet is configured to start automatically when the web application is deployed and started, that is when it is called
- otherwise it is called after the first request for the servlet is received
