JSP Interview Questions
Q1. What is JSP?
Ans: Java Server Pages innovation (JSP) is utilized to make dynamic page. It is an augmentation to the servlet innovation. A JSP page is inside changed over into servlet.
Q2. Make sense of JSP and tell its purposes.
Ans: JSP represents Java Server Pages. It is a show layer innovation free of stage. It accompanies SUN's J2EE stages. They resemble HTML pages however with Java code pieces implanted in them. They are saved with a .jsp expansion. They are gathered involving JSP compiler behind the scenes and create a Servlet from the page.
Q3. What is distinction between conceal remark and result remark?
Ans: The jsp remark is called conceal remark though html remark is called yield remark. On the off chance that client sees the wellspring of the page, the jsp remark won't be shown while html remark will be shown.
Q4. What is the prerequisite of a label library?
Ans: An assortment of custom labels is known as a Tag Library. Repeating errands are taken care of all the more effectively and reused across numerous applications to increment efficiency. They are utilized by Web Application fashioners who center around show as opposed to getting to information base or different administrations. A few well known libraries are String label library and Apache show label library.
Q5. Is JSP innovation extensible?
Ans: Yes. JSP innovation is extensible through the advancement of custom activities, or labels, which are epitomized in label libraries.
Q6. Make sense of JSP Technology.
Ans: JSP is a standard expansion of Java and is characterized on top of Servlet expansions. Its will likely improve on administration and production of dynamic pages. It is stage free, secure, and it utilizes Java as a server side prearranging language.
Q7. How might I carry out a string safe JSP page? What are the benefits and Disadvantages of utilizing it?
Ans: You can make your JSPs string protected by having them carry out the SingleThreadModel interface. This is finished by adding the order <%@ page isThreadSafe="false" %> inside your JSP page.
Q8. How could various submits due to invigorate button clicks be forestalled?
Ans: Using a Post/Redirect/Get or a PRG design, this issue can be tackled.
1. A structure filled by the client is submitted to the server utilizing POST or GET technique. The state in the data set and plan of action are refreshed.
2. A divert reaction is utilized to answer by the servlet for a view page.
3. A view is stacked by the program utilizing the GET order and no client information is sent. This is protected from different submits as it is a different JSP page.
Q9. How might we handle the exemptions in JSP ?
Ans: There are two methods for performing special case dealing with, one is by the errorPage component of page order, and second is by the mistake page component of web.xml record.
Q10. Is JSP innovation extensible?
Ans: Yes, JSP is effectively extensible by use and change of labels, or custom activities, typified in label libraries.
Q11. Separate among response.sendRedirect(url) and <jsp:forward page = … > .
Ans: <jsp.forward> component advances the solicitation object from 1 JSP record to another. Target record can be HTML, servlet or another JSP document, however it ought to be in a similar application setting as sending JSP file.sendRedirect send HTTP brief divert reaction to the program. The program then, at that point, makes another solicitation for the diverted page. It kills the meeting factors.
Q12. Might we at any point utilize the special case implied object in any jsp page ?
Ans: No. The exemption implied article must be utilized in the blunder page which characterizes it with the isErrorPage property of page order.
Q13. Might a resulting demand at any point be gotten to with one's servlet code, on the off chance that a solicitation property is now sent in his JSP?
Ans: The solicitation leaves scope, in this way, it can't be gotten to. In any case, in the event that a solicitation trait is set in one's servlet, it tends to be gotten to in his JSP.
A JSP is a server side part and the page in meant a Java servlet, and afterward executed. Just HTML code is given as result.
Q14. How is JSP utilized in the MVC model?
Ans: JSP is generally utilized for show in the MVC design (Model View Controller ) for example it assumes the part of the view. The regulator manages calling the model and the business classes which thus get the information, this information is then introduced to the JSP for delivering on to the client.
Q15. How to remember static records for a JSP page?
Ans: Static pages are constantly included utilizing JSP incorporate mandate. This way the consideration is acted in the interpretation stage once. Note that an overall URL should be provided for record property. Albeit static assets might be incorporated, it isn't liked as each solicitation requires consideration.
Q16. What are setting introduction boundaries?
Ans: Context instatement boundaries are determined by the <context-param> in the web.xml record, these are instatement boundary for the entire application and not well defined for any servlet or JSP.
Q17. How can it be that JComponent have add() and eliminate() techniques yet Component doesn't?
Ans: JComponent is a subclass of Container. It contains different Components and JComponents.
Q18. What is the distinction among ServletContext and PageContext?-
Ans: ServletContext gives the data about the holder while PageContext gives the data about the Request.
Q19. How might a string safe JSP page be executed?
Ans: It should be possible by having them carried out by the SingleThreadModel Interface. Add <%@page isThreadSafe="false" %> order in the JSP page.
Q20. What is the distinction in utilizing request.getRequestDispatcher() and context.getRequestDispatcher()?
Ans: Request.getRequestDispatcher(path) is utilized to make it we want to give the overall way of the asset though context.getRequestDispatcher(path) to make it we want to give the outright way of the asset.
Q21. How might the result of JSP or servlet page be kept from being reserved by the program?
Ans: Using proper HTTP header credits to forestall the powerful satisfied yield by a JSP page from being reserved by the program.
Q22. What is EL in JSP?
Ans: The Expression Language(EL) is utilized in JSP to improve on the availability of items. It gives many articles that can be utilized straightforwardly like param, requestScope, sessionScope, applicationScope, demand, meeting and so forth.
Q23. How to confine page mistakes show in a JSP page?
Ans: By setting up an "ErrorPage" property of PAGE catalog to the name of the blunder page in the JSP page, and afterward in the mistake jsp page set "isErrorpage="TRUE", Errors can be halted from getting shown.
Q24. What is fundamental contrasts between the JSP custom labels and java beans?
Custom labels can control JSP content though beans can't.
Complex tasks can be diminished to an essentially less complex structure with custom labels than with beans.
Custom labels require a lot more work to set up than do beans.
Custom labels are accessible just in JSP 1.1 and later, yet beans can be utilized in all JSP 1.x variants.
Q25. Might constructor at any point be utilized rather than init(), to instate servlet?
Ans: Yes, it is conceivable. However, it isn't favored on the grounds that init() was created in light of the fact that previous Java forms couldn't conjure constructors with contentions powerfully. So they couldn't dole out a servletConfig. Today, be that as it may, servlet compartments actually call just no-arg constructor. So there is no admittance to servletContext or servletConfig.