IGNOU BCA MCA - PROJECT VIVA Question Answer for JAVA - JSP Part XIII

IGNOU BCA MCA - PROJECT VIVA Question Answer for JAVA - JSP

JAVA - JSP Selected Question Answer - PART XIII

110. What are Directives ? What are the different types of Directives available in JSP ? Directives are instructions that are processed by the JSP engine, when the page is compiled to a servlet. Directives are used to set page-level instructions, insert data from external files, and specify custom tag libraries. Directives are defined between < %@ and % >.The different types of directives are shown below:

·         Include directive: it is used to include a file and merges the content of the file with the current page.

·         Page directive: it is used to define specific attributes in the JSP page, like error page and buffer.

·         Taglib: it is used to declare a custom tag library which is used in the page.

111. What are JSP actions ? JSP actions use constructs in XML syntax to control the behavior of the servlet engine. JSP actions are executed when a JSP page is requested. They can be dynamically inserted into a file, re-use JavaBeans components, forward the user to another page, or generate HTML for the Java plugin.Some of the available actions are listed below:

·         jsp:include – includes a file, when the JSP page is requested.

·         jsp:useBean – finds or instantiates a JavaBean.

·         jsp:setProperty – sets the property of a JavaBean.

·         jsp:getProperty – gets the property of a JavaBean.

·         jsp:forward – forwards the requester to a new page.

·         jsp:plugin – generates browser-specific code.

112. What are Scriptlets ? In Java Server Pages (JSP) technology, a scriptlet is a piece of Java-code embedded in a JSP page. The scriptlet is everything inside the tags. Between these tags, a user can add any valid scriplet.

113. What are Decalarations ? Declarations are similar to variable declarations in Java. Declarations are used to declare variables for subsequent use in expressions or scriptlets. To add a declaration, you must use the sequences to enclose your declarations.

114. What are Expressions ? A JSP expression is used to insert the value of a scripting language expression, converted into a string, into the data stream returned to the client, by the web server. Expressions are defined between <% = and %>tags.

115. What is meant by implicit objects and what are they ? JSP implicit objects are those Java objects that the JSP Container makes available to developers in each page. A developer can call them directly, without being explicitly declared. JSP Implicit Objects are also called pre-defined variables.The following objects are considered implicit in a JSP page:

·         application

·         page

·         request

·         response

·         session

·         exception

·         out

·         config

·         pageContext