Servlet and JSP interview questions

1.       What is JSESSIONID in Java? When does JSESSIONID gets created ?

2.       What is difference between include action and include directive in JSP?

3.       How do you define application wide error page in JSP?

4.       Difference between sendredirect and forward in Servlet ?

5.        How do remove variable using <c:set> tag from JSTL ?

6.       What is difference between Web Server and Application Server ?

7.        What is difference between URL Encoding and URL rewriting ?

8.        How do you get ServletContext reference inside Servlet ?

9.       What is difference between ServletContext and ServletConfig in Java ?

10.   What is difference between GET and POST method in HTTP protocol?

11.   What does load-on-start-up element in web.xml do?

12.   What are the phases of the servlet life cycle?

13.   What are the phases of the servlet life cycle?

14.   What is the difference between doGet() and doPost()?

15.   What is the difference between the include() and forward() methods?

16.   What is JSP ? Describe its concept.

17.   Explain the benefits of JSP?

18.   Is JSP technology extensible?

19.   Can we implement an interface in a JSP?

20.   What are the advantages of JSP over Servlet?

21.    Differences between Servlets and JSP?

22.    Explain the differences between ASP and JSP?

23.   Can I stop JSP execution while in the midst of processing a reuest?

24.   How to Protect JSPs from direct access ?

25.   Explain JSP API ?

26.   What are the lifecycle phases of a JSP?

27.   Explain the life-cycle mehtods in JSP?

28.    Difference between _jspService() and other life cycle methods.

29.   What is the jspInit() method?

30.   What is the _jspService() method?

31.   What is the jspDestroy() method?

32.   What JSP lifecycle methods can I override?

33.   How can I override the jspInit() and jspDestroy() methods within a JSP page?

34.   Explain about translation and execution of Java Server pages?

35.   Why is _jspService() method starting with an '_' while other life cycle methods do not?

36.   How to pre-compile JSP?

37.   The benefits of pre-compiling a JSP page?

38.   How many JSP scripting elements and explain them?

39.   What is a Scriptlet?

40.   What is a JSP declarative?

41.   How can I declare methods within my JSP page?

42.   What is the difference b/w variable declared inside a declaration and variable declared in scriplet ?

43.   What are the three kinds of comments in JSP and what's the difference between them?

44.   What is output comment?

45.    What is a Hidden Comment?

46.    How is scripting disabled?

47.    What are the JSP implicit objects?

48.    How does JSP handle run-time exceptions?

49.   How can I implement a thread-safe JSP page? What are the advantages and Disadvantages of using it?

50.   What is the difference between ServletContext and PageContext?

51.    Is there a way to reference the "this" variable within a JSP page?

52.    Can you make use of a ServletOutputStream object from within a JSP page?

53.   What is the page directive is used to prevent a JSP page from automatically creating a session?

54.   What's a better approach for enabling thread-safe servlets and JSPs? SingleThreadModel Interface or Synchronization?

55.   What are various attributes Of Page Directive ?

56.   Explain about autoflush?

57.   How do you restrict page errors display in the JSP page?

58.   What are the different scopes available fos JSPs ?

59.   when do use application scope?

60.   What are the different scope valiues for the ?

61.   How do I use a scriptlet to initialize a newly instantiated bean?

62.   Can a JSP page instantiate a serialized bean?

63.   How do we include static files within a jsp page ?

64.   In JSPs how many ways are possible to perform inclusion?

65.   In which situation we can use static include and dynamic include in JSPs ?

66.   Differences between static include directive and include action ?

67.   How many ways we can develop a servlet?

68.   What is the difference between CGI & Servlet?

69.   What is the difference between traditional & Fast CGI?

70.   What is the difference between ServletConfig & ServletContext?

71.   How to define a Servlet?

72.   Specify parallel technologies to the servlet?

73.   What is the difference between web server & web container?

74.   What is the difference between web server & application server?

75.   What are the various types of web containers?

76.   By using which 2 Packages we can implement Servlet?

77.   What is the purpose of ReuestDispatcher?

78.   What methods we can call on ReuesrDispatcher Object?

79.   Explain about SingleThreadModeal?

80.   Explain about SingleThreadModeal?

81.   What are the various methods present in SingleThreadModeal?

82.   What is the marker interface? Example?

83.   By using which interfaces we can implements Filter concept?

84.   What are the various listeners are available in Servlet specification?

85.   What are the various Event classes present in  Servlet Specification?

86.   By using which object we can send text data as response from the Servlet?

87.   By using which object we can read binary data send by the client?

88.   By using which object we can send binary data send as response from the  Servlet?

89.   What are the (various ) lifecycle methods of the Servlet?

90.   Explain the purpose of the init() method & How many times it will be excuted? When it will be executed?

91.   If init() method throws any Exception i.e; if init() method fails to execute then what will be happen?

92.   Is it possible to write constructor with in the Servlet?

93.   Why init() is reuired to perform initialization activities instead of constructor?

94.   Is it possible to perform Initialization activities with in the constructor?

95.   What is the purpose of service() & How Many times it will be Executed?

96.   Explain about destroy?

97.   Is it Possible to call destroy() method explicitly from service?

98.    With in the <servlet-mapping> how many url pattrerns taken at a time?

99.   Explain LifeCycle of the Servlet?

100.            What is the purpose of <load-on-startup>?

101.            What is the significance of the number for <load-on-startup>?

102.            If two servlets having same <load-on-startup>value then which wii be loaded first?

103.            Explain about GenericServlet?

104.            Which interfaces are implemented by GenericServlet?

105.            What is the necessity of having 2 init() methods with in the Servlet?

106.            Explain best way of overriding init()?

107.            What are various possible status code of response?

108.            Explain the difference between GET&POST?

109.            What are various HttpReuest methods?

110.            What is the difference between HEAD&GET?

111.            What is the difference between PUT&GPOST?

112.            Which Http methods are non-idempotent?

113.            Which Http methods are idempotent?

114.            In how many ways we can trigger a GET reuest?

115.            What is the default method for the form?

116.            What are different ways to trigger POST reuest?

117.            How many service() methods available in HttpServlet?

118.            Explain life cycle of getReuest?

119.            Is it recommended to override service() in Http based Servlet?

120.            If you are sending Get reuest but our Servlet contains doGet() & service() Methods then which method will be executed?

121.            If you are sending Get reuest but our Servlet doesn't contain doGet() what happen?

122.            Even though HttpServlet doesn't contain any abstract method why it is declared as abstract class?

123.            What are the various methods to retrieve from parameters?

124.            What is the purpose of  reuest Headers?

125.            How we can retrieve headers associated with the ServletReuest?

126.            To what value is a variable of the String type automatically initialized?How we can retrieve cookies from the reuest?

127.            By using which method we can get client &server information from the reuest?

128.            How we can add response headers to the ServletResponse?

129.            How we can set ContentType to the response?

130.            What is the MIME type?

131.            Is it possible to send multiple content type as response from the same servlet?

132.            Write Servlet code to send movie file as response?

133.            Is it possible to get PrintWriter & ServletOutputStream objects simultaneously?

134.            How we can implement Redirection mechanism?

135.            Explain, difference between sendRedirect&forword?

136.            How many times we can call sendRedirect() method with in the same Servlet?

137.            How we can add cookies to the response?

138.            Explain the directory structure of a web application?

139.            In which location we have to place static content?

140.            Is it possible to access resources present in the context root directly?

141.            Is WEB-INF folder mandatory for web application?

142.            Explain about web.xml?

143.            Where we have to place 3rd party jar files?

144.            If the reuired class file available in classes folder and lib folder jar file, then which one will get preference?

145.            Is there any alternate location to place servlet .class file Other than classes folder?

146.            Is it possible to access web.xml directory?

147.            Where we have to place tag libraries inside web application?

148.            Is it important the order of tags  in the web.xml?

149.            Can you specify any 10 tags of web.xml?

150.            With in the <web-app> which tags are mandatory?

151.            What is the purpose of <servlet-name>

152.            How many names are possible for a servlet in web-app?

153.            Is it possible to configure jsp's in web.xml?

154.            When we have to configure jsp's in web.xml?

155.            What is the purpose of Servlet initialization parameters and explain how to configure in web.xml?

156.            With in the servlet how we can access logical name of the servlet?

157.            With in the servlet how we can access Servlet initialization parameter?

158.            What is the ServletConfig object and explain the methods available in ServletConfig interface?

159.            What is the purpose of <load-on-startup>explain its advantages & disadvantages?

160.            If two Servlets having same<load-on-startup> values what will be happen?

161.            How many types of url patterns are possible according to Servlet specification?

162.            With in the <servlet-mapping>how many url pattrern tags we can take?

163.            How to configure defult Servlet in web.xml and when it will get chance for execution?

164.            What is the difference between url, uri & urn?

165.            How we can get Contextpath and uereyString directly with in the Servlet?

166.            What is the necessity of welcome-file and explain How to configure welcome files in web.xml?

167.            What is the default welcome-file?

168.             Is it possible to configure welcome file in folder wise?

169.            What is the necessity of error page and explain the process of Configuration in web.xml?

170.            How to send ErrorCode programmatically?

171.            What is the purpose of <mime-mapping>?

172.            Explain about of war file & the process of creation?

173.            What is the purpose of META-INF folder?

174.            Explain about MANIFEST.MF?

175.            Explain about <context-param>tag & <init-param>?

176.            What are the differences between Servlet initialization parameters& Context initialization parameters?

177.            How we can access context parameters and  servlet parameters  with in the Servlet?

178.            How we can declare context & Servlet <init-parameters>in web.xml?

179.            What is the scope of <context-param>&<init-param>?

180.            What are the difference between parameters & attributes?classhierarchy?

181.            What is the purpose of an attribute?

182.            What are various scopes available for Servlets?

183.            Explain the cases where we should go for each scope?

184.            explain the methods to perform following activities?

a)      Adding an attribute?

b)     Get the name of an attribute?

c)      Remove an attribute?

d)     Modify the value of an attribute?

e)      To display all attribute names present in a specified scope?

185.            If we store information in application scope  by default  it is available everywhere with in the web application, then what is the need of session and Reuest scopes?

186.            What is the purpose of ReuestDispatcher?

187.            How many possible ways we can get the ReuestDispatcher?

188.            What is the difference between obtaining ReuestDispatcher from ServletReuest and ServletContext object?

189.            What is the difference between forward() &include()?

190.            What is the difference between forward() &sendRedirect()?

191.            What is the foreign ReuestDispatcher & explain the process how we can get it?

192.            What are various attributes added by web container while forwarding & including?      What is the purpose of these attributes?

193.            What is the purpose of filter? Explain the cases where exactly reuired?

194.            By using which interfaces we can implement filter concepts?

195.             What is the purpose of FilterChain?

196.            How we can configure filter in web.xml?

197.            In how many ways we can map a filter?

198.            What is the purpose of <dispatcher> tag?

199.            What are the default values of <dispatcher> tag?

200.            What are allowed values of <dispatcher> tag?

201.            In filter chain in which order the filters will be executed?

202.            What is the difference between Filter interface doFilter() & FilterChain doFilter()?

203.            What is the intercepting filter design pattern?

204.            What is the purpose of wrapper?

205.            Explain the types of wrappers?

206.            Explain Decorator design pattern?

207.            Explain the cases where you used filters & wrappers in your previous project?

208.            What is the need of Session Management? Explain cases where   Session Management is reuired with example?

209.            What are the various Session Management techniues are available?

210.            Explain the process of creating Session object?

211.            What is the difference between getSession() & getSession(boolean b)?

212.            Explain with an example where getSession(false) is reuired?

213.            How we can invalidate a Session?

214.            Define Session management?

215.            How we can configure SessionTimeout in web.xml?

216.            What is the difference between <Session-timeout>and <SetMaxInactiveInterval>?

217.            How to know SessionCreation time & lastaccesed time?

218.            Explain the Session Management Mechanism by SessionAPI?

219.            What is the default session timeout?

220.            Explain Session Management by using Cookies?

221.            How the SessionId is exchanging between Client & Server?

222.            What is the difference between Session API & Cookie which approach is recommended?

223.            What is the difference between persistent and non persistent cookies?

224.            What is URL Rewriting?

225.            By using which Methods we can implement URLRewriting?

226.            BY using which methods we can identify under laying Session Management techniue?

227.            Explain advantages & disadvantages of cookies, URL Writing, Session API

228.            Explain the purpose of Listener?

229.            What are the various listeners are available according to Servlet specification?

230.            What is the difference between ServletReuestListener and ServletReuestAttributeListener?

231.            How to configure listener in web.xml?

232.            To print hit count of the web application which listener is reuired to use?

233.            To print the no of active session objects at server side which listener is responsible?

234.            What is the difference between HSAL & HSBL?

235.            What are various methods present in binding listeners?

236.            Explain about HttpSessionActivationListener?

237.            At the time of application deployment to perform certain activities which listener is responsible?

238.            What are various listeners which are not reuired to configure in web.xml?

239.            What are various event classes available in ServletSpecification?

240.            Is it possible to configure more than one listener of same type?

241.            If you are configures more than one listener of the same type then in which order listener will be executed?

242.            Who is responsible to perform instantiation of listener?

243.            At what time listener classes will be instantiated?

244.            What is the difference between declarative Security & programmatic security?

245.            By using which methods we can implement programmatic Security?

246.            What is the purpose of <security-role-ref>?

247.            How we can configure users in Tomcat?

248.            In your previous project how you implement security?

249.            In your previous project what type of authentication used?