This set of Advanced Java Multiple Choice Questions & Answers (MCQs) focuses on “Servlet”.
1. How constructor can be used for a servlet?
b) Constructor function
c) Initialization and Constructor function
d) Setup() method
Explanation: We cannot declare constructors for interface in Java. This means we cannot enforce this requirement to any class which implements Servlet interface.
Also, Servlet requires ServletConfig object for initialization which is created by container.
2. Can servlet class declare constructor with ServletConfig object as an argument?
Explanation: ServletConfig object is created after the constructor is called and before init() is called. So, servlet init parameters cannot be accessed in the constructor.
3. What is the difference between servlets and applets?
i.Servlets execute on Server; Applets execute on browser
ii.Servlets have no GUI; Applet has GUI
iii.Servlets creates static web pages; Applets creates dynamic web pages
iv.Servlets can handle only a single request; Applet can handle multiple requests
a) i,ii,iii are correct
b) i,ii are correct
c) i,iii are correct
d) i,ii,iii,iv are correct
Explanation: Servlets execute on Server and doesn’t have GUI. Applets execute on browser and has GUI.
4. Which of the following code is used to get an attribute in a HTTP Session object in servlets?
a) session.getAttribute(String name)
b) session.alterAttribute(String name)
c) session.updateAttribute(String name)
d) session.setAttribute(String name)
Explanation: session has various methods for use.
5. Which method is used to get three-letter abbreviation for locale’s country in servlets?
Explanation: Each country is usually denoted by a 3 digit code.ISO3 is the 3 digit country code.
6. Which of the following code retrieves the body of the request as binary data?
a) DataInputStream data = new InputStream()
b) DataInputStream data = response.getInputStream()
c) DataInputStream data = request.getInputStream()
d) DataInputStream data = request.fetchInputStream()
Explanation: InputStream is an abstract class. getInputStream() retrieves the request in binary data.
7. When destroy() method of a filter is called?
a) The destroy() method is called only once at the end of the life cycle of a filter
b) The destroy() method is called after the filter has executed doFilter method
c) The destroy() method is called only once at the begining of the life cycle of a filter
d) The destroyer() method is called after the filter has executed
Explanation: destroy() is an end of life cycle method so it is called at the end of life cycle.
8. Which of the following is true about servlets?
a) Servlets execute within the address space of web server
b) Servlets are platform-independent because they are written in java
c) Servlets can use the full functionality of the Java class libraries
d) Servlets execute within the address space of web server, platform independent and uses the functionality of java class libraries
Explanation: Servlets execute within the address space of a web server. Since it is written in java it is platform independent. The full functionality is available through libraries.
9. How is the dynamic interception of requests and responses to transform the information done?
a) servlet container
b) servlet config
c) servlet context
d) servlet filter
Explanation: Servlet has various components like container, config, context, filter. Servlet filter provides the dynamic interception of requests and responses to transform the information.
10. Which are the session tracking techniques?
i. URL rewriting
ii. Using session object
iii.Using response object
iv. Using hidden fields
v. Using cookies
vi. Using servlet object
a) i, ii, iii, vi
b) i, ii, iv, v
c) i, vi, iii, v
d) i, ii, iii, v
Explanation: URL rewriting, using session object, using cookies, using hidden fields are session tracking techniques.
Sanfoundry Global Education & Learning Series – Java Programming Language.