60 TOP Java Beans Interview Questions and Answers for Freshers

Java Beans technical interview questions and answers are available for beginners to expert level
1 . What are Java Beans?

2 . Why do I get a NullPointerException when loading a JAR file into the BeanBox?

3 . What is bean persistance property?

4 . What are externizable interface?

5 . What are the purpose of introspection?

6 . What is property editor in java beans?

7 . Write a simple bean program?

8 . Difference between java bean and bean?

9 . What is a Bean? Why is not a Bean an Applet?

10 . Why are component architectures useful?

11 . Is JavaBeans a complete component architecture?

12 . Why a component architecture for the Java platform?

13 . What kind of industry support exists for JavaBeans?

14 . Are there JavaBeans components available that I can buy today?

15 . Why nobody at Sun wants to read the messages sent to java-beans@java.sun.com?

16 . What is the relationship between Sun s JFCs and JavaBeans?

17 . Why do I get a duplicate name error when loading a JAR file?

18 . What are the security implications for downloading Beans over the Internet?

19 . When will JavaBeans be supported on the [fill in the blank] platform/operating system?

20 . What is entity reference?

21 . What is an entity?

22 . What is enterprise bean provider?

23 . What is Enterprise JavaBeans Query Language?

24 . What is Enterprise JavaBeans?

25 . What is enterprise information system?

26 . What is EJB server?

27 . What is entity bean?

28 . What is EJB object?

29 . What is EJB Home object?

30 . What is EJB context?

31 . What is EJB container?

32 . What is bean customization?

33 . What are introspection API in java beans?

34 . What is introspection properties in java beans?

35 . How to control serialization in java beans?

36 . What is the serializable class in java beans?

37 . How to create bound property in bean application?

38 . What is Glasgow?

39 . How does the InfoBus relate to JavaBeans?

40 . Will the general public have access to the InfoBus API s?

41 . Is the InfoBus client side only?

42 . Difference between java Beans and Enterprise Java Beans?

43 . What is the relation between the InfoBus and RMI?

44 . Why is the JavaBeans Bridge for ActiveX only available on Windows/X86?

45 . Who is developing the JavaBeans Migration Assistant to ActiveX?

46 . What are/is Enterprise JavaBeans?

47 . What are the properties of java beans?

48 . What is the InfoBus?

49 . Does the InfoBus compete with JavaBeans?

50 . Is InfoBus easy to use?

51 . JavaBeans has mechanisms like bound properties for data transfer between components. Why is the InfoBus necessary?

52 . Can both Java applets and JavaBeans components use the InfoBus?

53 . Can JavaBeans use DCOM as its network model?

54 . Why would a developer need the JavaBeans Migration Assistant for ActiveX?

55 . How and when will the JavaBeans Migration Assistant to ActiveX be available?

56 . How to implement a bound property in your bean application?

57 . What is the relationship between Enterprise JavaBeans and JavaBeans?

58.  What is property editor in java beans?

59. What are the purpose of introspection?

60. What are externizable interface?

61. What is bean persistance property?

How do you restrict page errors display in the JSP page? | Java JSP

You first set "Errorpage" attribute of PAGE directory to the name of the error page (ie Errorpage="error.jsp")in your jsp page .Then in the error jsp page set "isErrorpage=TRUE". When an error occur in your jsp page it will automatically call the error page.

How do I prevent the output of my JSP or Servlet pages from being cached by the browser? | Java JSP

You will need to set the appropriate HTTP header attributes to prevent the dynamic content output by the JSP page from being cached by the browser. Just execute the following scriptlet at the beginning of your JSP pages to prevent them from being cached at the browser. You need both the statements to take care of some of the older browser versions.

How can I enable session tracking for JSP pages if the browser has disabled cookies? | Java JSP

We know that session tracking uses cookies by default to associate a session identifier with a unique user. If the browser does not support cookies, or if cookies are disabled, you can still enable session tracking using URL rewriting. URL rewriting essentially includes the session ID within the link itself as a name/value pair.
However, for this to be effective, you need to append the session ID for each and every link that is part of your servlet response. Adding the session ID to a link is greatly simplified by means of of a couple of methods: response.encodeURL() associates a session ID with a given URL, and if you are using redirection, response.encodeRedirectURL() can be used by giving the redirected URL as input.
Both encodeURL() and encodeRedirectedURL() first determine whether cookies are supported by the browser; if so, the input URL is returned unchanged since the session ID will be persisted as a cookie. Consider the following example, in which two JSP files, say hello1.jsp and hello2.jsp, interact with each other.

Why does JComponent have add() and remove() methods but Component does not? | Java JSP

because JComponent is a subclass of Container, and can contain other components and jcomponents. How can I implement a thread-safe JSP page? - You can make your JSPs thread-safe by having them implement the SingleThreadModel interface. This is done by adding the directive
<%@ page isThreadSafe="false" % > within your JSP page.

How do I include static files within a JSP page? | Java JSP

Static resources should always be included using the JSP include directive. This way, the inclusion is performed just once during the translation phase. Do note that you should always supply a relative URL for the file attribute. Although you can also include static resources using the action, this is not advisable as the inclusion is then performed for each and every request.

What are stored procedures? How is it useful?

A stored procedure is a set of statements/commands which reside in the database. The stored procedure is pre-compiled and saves the database the effort of parsing and compiling sql statements every time a query is run. Each database has its own stored procedure language, usually a variant of C with a SQL preproceesor. Newer versions of db’s support writing stored procedures in Java and Perl too. Before the advent of 3-tier/n-tier architecture it was pretty common for stored procs to implement the business logic( A lot of systems still do it). The biggest advantage is of course speed. Also certain kind of data manipulations are not achieved in SQL. Stored procs provide a mechanism to do these manipulations. Stored procs are also useful when you want to do Batch updates/exports/houseKeeping kind of stuff on the db. The overhead of a JDBC Connection may be significant in these cases.