1 T.Y. B.Sc. (IT) : Sem. V Advanced Java Time : 2½ Hrs.] Prelim Question Paper Solution [Marks : 75 Q.1 Attempt the following (any TWO) [10] Q.1(a) What is the default layout of the frame? Explain the same. [5] (A) [Explanation 2 marks, Diagram 1 marks, Program 2 marks] BORDERLAYOUT is the default layout of the frame. It splits the container into five distinct sections where each section can hold one component. The five sections of the BorderLayout are known as NORTH, SOUTH, EAST, WEST and CENTER as shown in the diagram. To add a component to a BorderLayout, one needs to specify which section one wants it placed. JFrame frm1 = new JFrame(); JPanel op = new JPanel(); frm1 .add (op, BorderLayout.NORTH); Example import java.awt.*; import javax.swing.*; class BorderTest extends JFrame { public static void main(String[] args) { JFrame window = new BorderTest(); window.setVisible(true); } BorderTest() { Vidyalankar
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T.Y. B.Sc. (IT) : Sem. V Advanced Java
Time : 2½ Hrs.] Prelim Question Paper Solution [Marks : 75
Q.1 Attempt the following (any TWO) [10]Q.1(a) What is the default layout of the frame? Explain the same. [5](A) [Explanation 2 marks, Diagram 1 marks, Program 2 marks]
BORDERLAYOUT is the default layout of the frame. It splits the container into five distinct sections where each section can
hold one component. The five sections of the BorderLayout are known as NORTH, SOUTH,
EAST, WEST and CENTER as shown in the diagram. To add a component to a BorderLayout, one needs to specify which
section one wants it placed.
JFrame frm1 = new JFrame(); JPanel op = new JPanel(); frm1 .add (op, BorderLayout.NORTH);
Example import java.awt.*; import javax.swing.*;
class BorderTest extends JFrame {
public static void main(String[] args) { JFrame window = new BorderTest(); window.setVisible(true); } BorderTest() {
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//... Create components (but without listeners) JButton north = new JButton("North"); JButton east = new JButton("East"); JButton south = new JButton("South"); JButton west = new JButton("West"); JButton center = new JButton("Center"); //... Create content pane, set layout, add components JPanel content = new JPanel(); content.setLayout(new BorderLayout()); content.add(north , BorderLayout.NORTH); content.add(east , BorderLayout.EAST); content.add(south , BorderLayout.SOUTH); content.add(west , BorderLayout.WEST); content.add(center, BorderLayout.CENTER); //... Set window characteristics. setContentPane(content); setTitle("BorderTest"); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); } }
Q.1(b) Explain the Java event delegation model. [5](A) [Explanation 2 marks, Explanation of Event, event source,
Event Listeners – 2marks, Program 1 marks] The Java event delegation model. Java Event Delegation model defines standard and consistent
mechanisms to generate and process events. The source generates an event and sends it to one or more listeners. The listener simply waits until it receives an event. Once the event is received, the listener processes the event and
returns. The advantage of this design is that the application logic that processes
events is cleanly separated from the user interface logic that generates those events.
The user interface element is able to ‘delegate’ the processing of an event to a separate piece of code.
In this event model, listeners must register with a source in order to receive an event notification.
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This provides an important benefit : notifications are sent only to listeners that want to receive them. Events : In the delegation model, an event is an object that describes a
state change in a source. It can be generated as a consequence of a person interacting with the elements in a graphical user interface. Example Pressing a button.
Event Source : is an object that generates an event. This occurs when the internal state of that object change in some way. A source must register listeners in order to receive notifications about a specific type of event.
Example: public void addTypeListener(TypeListener el) Event Listeners : a Listener is an object that is notified when an event
occurs. It has two requirements, first, it must have been registered with one or more sources to receive notifications about specific type of events and second, it must implement methods to receive and process these notifications. Example : import java.awt.*; import java.awt.event.*; import java.applet.*; /* <applet code=”SimpleKey” width=300 height=300> </applet> */ public class SimpleKey extends Applet implements KeyListener { String msg = “ ” ; int X = 10, Y=20; public void init() { addKeyListener(this); } public void KeyPresses(KeyEvent ke) { showStatus(“Key Down”); } public void KeyReleased(KeyEvent ke)
Q.1(c) Write a short note on “Event Listeners”. Explain the working with
code [5]
(A) [Explanation 1 marks, Example 2 marks, Program 2 marks] A listener is an object that is notified when an event occurs. It has two major requirements. It must have been registered with one or
more sources to receive notifications about specific types of events. Second, it must implement methods to receive and process these
notifications. The methods that receive and process events are defined in a set of
interfaces found in java.awt.event. For example: The MouseMotionListener interface defines two methods
to receive notifications when the mouse is dragged or moved. void mouseDragged(MouseEvent me) – method is called multiple times as the mouse is dragged. void mouseMoved(MouseEvent me) - method is called multiple times as the mouse is moved.
Any object may receive and process one or both of these events if it provides an implementation of this interface.
public class MouseEvents extends Applet implements MouseListener, MouseMotionListener { String msg = " "; int mouseX = 0, mouseY = 0; public void init() { addMouseMotionListener(this); } //handle mouse dragged public void mouseDragged(MouseEvent me) { //save coordinates mouseX = me.getX(); mouseY = me.getY(); msg = "*"; showStatus("Dragging mouse at " + mouseX + ", " + mouseY); } //handle mouse moved public void mouseMoved(MouseEvent me) { //show status showStatus("Moving mouse at " + me.getX()+ ", " + me.getY()); } //Display message in the applet window at current X,Y location public void paint(Graphics g) { g.drawString(msg,mouseX,mouseY); } }
Q.1(d) What are adapter classes? What are inner classes? Explain withexamples.
[5]
(A) Adapter Classes: [1 Marks] An adapter class provides the default(empty) implementation of all
methods in an event listener interface. Adapter classes are very useful when one wants to process only few of
the events that are handled by a particular event listener interface. One can define a new class by extending one of the adapter classes and
implement only those events relevant to the program.
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Example : [1½ Marks] import java.awt.*; import java.awt.event.*; import java.applet.*; public class AdapterDemo extends MouseAdapter { public void init() { addMouseListener(new MyMouseAdapter(this)); addMouseMotionListener(new MyMouseMotionAdapter(this)); } } class MyMouseAdapter extends MouseAdapter { AdapterDemo adDemo1; public MyMouseAdapter(AdapterDemo adDemo2) {
adDemo1 = adDemo2; } //handles mouse clicked and ignores all other events. public void mouseClicked(MouseEvent me) { adDemo1.showStatus(“Mouse clicked”); } }
Inner Classes [1 Marks] Inner classes are class within Class. Inner class instance has special relationship with Outer class. This special relationship gives inner class access to member of outer class as if they are the part of outer class. Example: [1½ Marks] import java.applet.*; import java.awt.event.*; /* <applet code=”InnerClassDemo width=200 height=200> </applet> */
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public class InnerClassDemo extends Applet { public void init() { addMouseListener(new MyMouseAdapter()); } class MyMouseAdapter extends MouseAdapter { public void mousePressed(MouseEvent me) { showStatus(“Mouse Pressed”); } } }
Q.2 Attempt the following (any TWO) [10]Q.2(a) Write a Java program using JCheckBox and JRadioButton to get the
following output. Once the items are chosen and Place order buttonis clicked, the items selected should be displayed in the commandline.
[5]
(A) import java.awt.*; import java.awt.event.*; import javax.swing.*; class test extends Jprame implements ActionListener {
Q.2(b) How can a Tree structure be created in Swing? Explain.in
JOptionPane in detail. [5]
(A) A tree structure is created in the following ways [2 Marks] The node is represented in Swing API as TreeNode which is an interface.
The interface MutableTreeNode extends this interface which represents a mutable node. Swing API provides an implementation of this interface in the form of DefaultMutableTreeNode class.
DefaultMutableTreeNode class is to be used to represent the node. This class is provided in the Swing API. This class has a handy add() method which takes in an instance of MutableTreeNode.
So, first root node is created. And then recursively nodes are added to that oot.
import java.awt.event.*; [3 Marks] import java.awt.*; import javax.swing.event.*; import javax.swing.tree.*; import javax.swing.*; public class JTreeExample extends JFrame{ public JTreeExample() { this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); DefaultMutableTreeNode everything = new DefaultMutableTreeNode("Everything"); JTree avm = new JTree(everything); DefaultMutableTreeNode animal = new DefaultMutableTreeNode("Animal"); everything.add(animal); animal.add(new DefaultMutableTreeNode("Cat")); animal.add(new DefaultMutableTreeNode("Dog")); animal.add(new DefaultMutableTreeNode("Fish")); DefaultMutableTreeNode vegetable = new
Container con = getContentPane(); con.add(avm, BorderLayout.CENTER); setSize(200,300); setVisible(true); } public static void main(String args[]) { new JTreeExample(); } }
Q.2(c) How to divide frame window in two parts. Explain with code
specification. [5]
(A) A frame window can be divided into two parts using JSplitPane component. [2 Marks]
A frame can be divided into two parts either vertically or horizontally. In the following code, a frame is divided into two parts horizontally. Firstly, the object of JSplitPane is created. Then its setOrientation() method is used to set the orientation, either
Q.2(d) What is the purpose of tabbed panes? Explain with suitable
example. [5]
(A) Purpose of TabbedPanes : [2 Marks] This component lets the user switch between a group of components by
clicking on a tab with a given title and/or icon. Tabs are added to a TabbedPane object by using the addTab() or an
insertTab() methods.
Example: [3 Marks] import javax.swing.JTabbedPane; import javax.swing.*; import java.awt.*; import java.awt.event.*; public class JTabbedPaneDemo extends JFrame { public static void main(String args[]) { JTabbedPaneDemo d = new JTabbedPaneDemo(); JTabbedPane p = new JTabbedPane(); p.addTab("Cities", new CitiesPanel()); p.addTab("Colors", new ColorsPanel()); d.add(p); d.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); d.setSize(500,500); d.setVisible(true); } } class CitiesPanel extends JPanel { public CitiesPanel () { JButton b1 = new JButton("New York");
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add(b1); } } class ColorsPanel extends JPanel { public ColorsPanel () { JButton b1 = new JButton("Blue"); add(b1); } }
Q.3 Attempt the following (any TWO) [10]Q.3(a) Write a Servlet program to display the simple sentence Welcome
along with the name entered by the user through an HTML form. [5]
Q.3(b) Explain the generic servlet and HTTP servlet. [5](A) Generic Servlet: [1 Marks]
GenericServlet class is direct subclass of Servlet interface. Generic Servlet is protocol independent.It handles all types of protocol
like http, smtp, ftp etc. Generic Servlet only supports service() method.It handles only simple
request . public void service(ServletRequest req,ServletResponse res ). A generic servlet should override its service() method to handle
requests as appropriate for the servlet. The service() method accepts two parameters: a request object and a
response object. The request object tells the servlet about the request, while the response object is used to return a response.
Generic Servlet only supports service() method.
Generic Servlet Request Handling
[1½ Marks] Vidyala
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HttpServlet: [1 Marks] HttpServlet class is the direct subclass of Generic Servlet. HttpServlet is protocol dependent. It handles only http protocol. HttpServlet supports public void service(ServletRequest
req,ServletResponse res ) and protected void service(HttpServletRequest req,HttpServletResponse res).
HttpServlet supports also doGet(),doPost(),doPut(),doDelete(),doHead(),doTrace(),doOptions() etc.
An HTTP servlet usually does not override the service() method. Instead, it overrides doGet() to handle GET requests and doPost() to handle POST requests.
An HTTP servlet can override either or both of these methods, depending on the type of requests it needs to handle.
The service() method of HttpServlet handles the setup and dispatching to all the doXXX() methods
HTTP servlet request handling
Q.3(c) Explain the importance of request dispatcher of servlet in inter
servlet communication. [5]
(A) RequestDispatcher object: [1 Marks] RequestDispatcher object is used in the servlets to implement request
dispatching. A Servlet recives the client request, does the processing partially and
hands over the request processing duty to another servlet. This mechanism is known as request dispatching.
Inter servlet communication is implemented using RequestDispacher object. In a servlet one can get RequestDispatcher object reference in two ways. [2 marks] 1. RequestDispatcher rd = context.getRequestDispatcher(String
If the ServletContext object is used to get the RequestDispatcher, absolute URL of the target resource is to be supplied. If HttpServletRequest is used to get the RequestDispatcher object, only relative url of the target resource is to be supplied. Request dispatching can be implemented in two ways. [2 Marks]
Forward mechanism - Forwards a request from a servlet to another resource such as Servlet, JSP or HTML file on the server.
Include mechanism - includes the contents of a resource such as Servlet, JSP, HTML file in the response.
Q.3(d) Explain the life cycle phases of servlet. [5](A) [Listing of phases 1 marks, Explanation of all phases 3 marks,
Diagram 1 marks] Servlet Lifecycle [1 Marks] The servlet lifecycle consists of the following phases: Loaded Instantiated Initialized Service request Destroyed Finally garbage collected 1. Loaded - As soon as there is a request for a servlet, it is loaded on the
JVM, if it does not exist. A servlet is only loaded once. 2. Instantiated - After loading the servlet, it is instantiated i.e. an object
of the requested servlet class is created to service the request. 3. Initialized - Post instantiation, the servlet’s init(ServletConfig config)
method is called in order to initialize the servlet.
The init() method is defined as public void init(ServletConfig config) throws ServletException During initialization, the servlet has access to two objects: ServletConfig ServletContext
The following are the most common tasks that are implemented in the init() method: Reading initialization parameters Reading configuration data from persistent resource like a config
file Initializing a database driver Opening a JDBC connection Writing of information to a network resource
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4. Service Request - Only after the completion of the init() method, the service() method is invoked.
Once the server has loaded and initialized the servlet, it is able to handle client requests through the service() method. Each client request to the service() method is run in a separate servlet thread. The service() method is defined as follows: public void service(ServletRequest req, ServletResponse res) throws ServletException, IOException The ServletRequest object helps in accessing the original request data and the ServletResponse object provides methods that help in building a response.
5. Destroyed - Post servicing the request, the servlet can be unloaded by
calling the destroy() method.ll resources which were allocated by init() should be released by destroy(). The destroy() method is defined as public void destroy() throws ServletException This method is only called once in the lifetime of a servlet. The most common tasks in the destroy() method are: Synchronizing cleanup tasks such as closing open resources or closing
a connection pool Informing other applications that the servlet will no longer be available
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Q.4 Attempt the following (any TWO) [10]Q.4(a) What is JDBC driver? Explain the types of JDBC drivers. [5](A) JDBC driver : JDBC drivers implement the defined interfaces in the JDBC
API for interacting with your database server. For example, using JDBC drivers enable you to open database connections and to interact with it by sending SQL or database commands then receiving results with Java. The Java.sql package that ships with JDK contains various classes with their behaviours defined and their actual implementaions are done in third-party drivers. Third party vendors implements thejava.sql.Driver interface in their database driver. JDBC Driver Types: There are four categories of drivers by which developer can apply a connection between Client (The JAVA application or an applet) to a DBMS. 1. Type 1 Driver : JDBC-ODBC Bridge. (Platform dependent) 2. Type 2 Driver : Native-API Driver (Partly Java driver). (Platform dependent) 3. Type 3 Driver : Network-Protocol Driver (Pure Java driver for database
connected to database). (Platform independent) 1. Type 1 Driver: JDBC-ODBC Bridge :
The JDBC type 1 driver which is also known as a JDBC-ODBC Bridge converts JDBC methods into ODBC function calls. Sun provides a JDBC-ODBC Bridge driver by “sun.jdbc.odbc.JdbcOdbcDriver”. The driver is a platform dependent because it uses ODBC which is depends on native libraries of the operating system and also the driver needs other installation for example, ODBC must be installed on the computer and the database must support ODBC driver. Type 1 is the simplest compare to all other driver but it’s a platform specific i.e. only on Microsoft platform. The JDBC-ODBC Bridge is use only when there is no PURE-JAVA driver available for a particular database.
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Architecture Diagram:
Process: Java Application → JDBC APIs → JDBC Driver Manager → Type 1 Driver → ODBC Driver → Database library APIs → Database Advantage: Connect to almost any database on any system, for which ODBC
driver is installed. It’s an easy for installation as well as easy(simplest) to use as
compare the all other driver. Disadvantage: The ODBC Driver needs to be installed on the client machine. It’s a not a purely platform independent because its use ODBC which is
depends on native libraries of the operating system on client machine. Not suitable for applets because the ODBC driver needs to be
installed on the client machine.
2. Type 2 Driver: Native-API Driver (Partly Java driver) The JDBC type 2 driver uses the libraries of the database which is available at client side and this driver converts the JDBC method calls into native calls of the database so this driver is also known as a Native-API driver.
Advantage: There is no implantation of JDBC-ODBC Bridge so it’s faster than a
type 1 driver; hence the performance is better as compare the type 1 driver (JDBC-ODBC Bridge).
Disadvantage: On the client machine require the extra installation because this
driver uses the vendor client libraries. The Client side software needed so cannot use such type of driver in
the web-based application. Not all databases have the client side library. This driver supports all JAVA applications except applets.
3. Type 3 Driver: Network-Protocol Driver (Pure Java driver for database Middleware) The JDBC type 3 driver uses the middle tier(application server) between the calling program and the database and this middle tier converts JDBC method calls into the vendor specific database protocol and the same driver can be used for multiple databases also so it’s also known as a Network-Protocol driver as well as a JAVA driver for database middleware.
Driver → Middleware (Server)→ any Database Advantage: There is no need for the vendor database library on the client
machine because the middleware is database independent and it communicates with client.
Type 3 driver can be used in any web application as well as on internet also because there is no any software require at client side.
A single driver can handle any database at client side so there is no need a separate driver for each database.
The middleware server can also provide the typical services such as connections, auditing, load balancing, logging etc.
Disadvantage: An Extra layer added, may be time consuming. At the middleware develop the database specific coding, may be
increase complexity.
4. Type 4 Driver: Native-Protocol Driver (Pure Java driver directly connected to database) The JDBC type 4 driver converts JDBC method calls directly into the vendor specific database protocol and in between do not need to be converted any other formatted system so this is the fastest way to communicate quires to DBMS and it is completely written in JAVA because of that this is also known as the “direct to database Pure JAVA driver”.
Advantage: It’s a 100% pure JAVA Driver so it’s a platform independence. No translation or middleware layers are used so consider as a faster
than other drivers. The all process of the application-to-database connection can manage
by JVM so the debugging is also managed easily. Disadvantage: There is a separate driver needed for each database at the client side. Drivers are Database dependent, as different database vendors use
different network protocols. Q.4(b) Explain the prepared statement with suitable example. [5](A) Prepared Statements [2 Marks]
PreparedStatement object is used to send SQL statements to the database.
This special type of statement is derived from a class, Statement. Although PreparedStatement objects can be used for SQL statements
with no parameters, they can also used with SQL statements that take parameters.
The advantage to this is that in most cases, this SQL statement is sent to the DBMS, where it is compiled. As a result, the PreparedStatement object contains not just a SQL statement, but a SQL statement that has been precompiled. This means that when the PreparedStatement is executed, the DBMS can just run the PreparedStatement SQL statement without having to compile it first.
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The advantage of using SQL statements that take parameters is that you can use the same statement and supply it with different values each time you execute it.
The syntax: [1 Marks] PreparedStatement objectname = connctionObject.prepareStatement(SQLQrery) ;
For example PreparedStatement p = conn.prepareStatement(queryString) ;
Where conn is the connection object.
Before executing the Preparedstatement, the host variables must be bound to actual values with a set method.
Then execute the statement by calling object’s executeUpdate method. p.executeUpdate();
Example [2 Marks] String sql = “select * from people where firstname=? And lastname=?” ; preparedStatement ps = connection. preparedStatement(sql); preparedStatement.setString(1, “John”); preparedStatement.setString(2, “Smith”); ResultSet rs = preparedStatement.executeQuery();
Q.4(c) Enlist the implicit objects of JSP. Explain any 4 of them in detail. [5](A) [Listing 1 marks, Explanation of 4 objects 4 marks]
Following are the implicit objects of JSP 1. Request 2. Response 3. Out 4. Session 5. Application 6. Config 7. PageContext 8. Page 9. Exception 1. Request
The Request object provides access to all information associated with a request including its source, the requested URL and any headers, cookies or parameters associated with the request.
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It encapsulates the request coming from the client and being processed by the JSP.
The Request object is an instance of javax.servlet.HttpServletRequest The following are the methods available to the request object
Method Description
getParameters() Returns the value of a request parameter as a String.
getParameterNames() Returns an Enumeration of String objets containing the name of the parameters contained in this request
getParameterValues() Returns an array objects containing all the values, the given request parameter has.
2. Response : This object represents the response sent back to the user browser
as a result of processing the JSP page. It encapsulates the response generated by the JSP. This is the response being sent back to a client browser in response
to its request. The Response object is an instance of
javax.servlet.http.HttpServletResponse The following are the methods available to the response object
Method Description addCookie() Adds the specified cookie to the response. sendRedirect() Sends a temporary resirect response to the client
using the specified redirect location URL.
3. Out : The Out object represents the output stream of the JSP page, the
contents of which are being sent to a client browser. The out object is the PrintWriter, which is used to send output to
the client. The following are the methods available to the out object
Method Description clear() Clears the contents of the buffer and throws an
exception if some data has already been written to the output stream.
close() Flushes and then closes the output stream. print() Prints the specified primitive data type such as
Object or String to the client.
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4. Session: A session refers to the entire conversation between a client and a
server. It allows accessing a client’s session data, managed by the server. Sessions are created automatically. Sessions are used to maintain state and user identity across multiple
page requests. The following are the methods available to the session object
Method Description inNew() A session is considered to be new if it is been
created by the server, but the clients has not yet acknowledged joining the session.
invalidate() Discards the session, releasing any objects stored as attributes.
getAttribute() Retrieves the object associated with the named attribute.
Q.4(d) Write a jsp that accepts user-login details and forward the result
either “Access Granted” or “Access Denied” to result.jsp. 1. HTML 2. JSP 3. JSP
Q.5 Attempt the following (any TWO) [10]Q.5(a) Enlist the lifecycle phases of JSF. Explain the following phases in
detail. [5]
(A) [Listing 1 Marks, Explanation of 4 phases 4 marks]
The JSF lifecycle has the following six phases, which are defined by the JSF specification : Restore view Apply Request Values Process validations Update Model Values Invoke application Render Response
These six phases show the order in which JSF typically processes a FORM. Restore View : in this first phase of JSF life cycle, a request comes through the
FacesServlet controller. When a request is made for a JSF page, the JSF implementation t
the JSF framework controller uses the view ID to look up the components for the current view. If the view does not already exist, the JSF controller creates it. If the view already exists, the JSF controller uses it. Te view contains all the GUI components.
During this phase, the JSF implementation- Builds the view of the page. Wires event handlers and validators to components in the view
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Saves the view in the FacesContext instance, which contains all the information needed to process a single request.
This phase presents three view instances : new view, initial view and postback.
New view - JSF builds the view of the Faces page and wires the handlers and validators to components in the view and this view is saves in the FAcesContext object.
Inital view - JSF creates an empty view. It will be populated as the user causes events to occur. From an initial view, JSF advances directly to the render response phase.
� Postback - , the view corresponding to the page already exists, so it needs only to be restored
Apply Request Values the purpose of the apply request phase is for each component to
retrieve current state. The components must first be retrieved or created from the FacesContext object, followed by their values.
If a component’s immediate event handling property is not set to true, the values are just converted.
� If a component’s immediate event handling property is set to true, the values are converted to the proper type and validated.
Update Model Values It updates the actual values of the server-side model by updating the
properties of managed beans. Only bean properties that are bound to component’s value will be
updated. This phase happens after validation, so one can be sure that the values
copied to the bean’s properties are valid.
Render Response In this phase, the view is displayed with all of its components in their
current state.
Q.5(b) Explain the advantages of EJB. [5](A) Complete focus only on Business Logic [5 Marks]
Enterprise Beans live and run in the server under the control of an EJB container.
The EJB container provides all the big infrastructure services such as Security, Concurrency, Transaction management, Networking, Resource management, Persistence, Massaging and Customization during deployment.
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Developer can use these services with minimal effort and time, thus making writing an enterprise bean as simple as writing a Java class.
EJB model seperates system level services from the business logic. This allows the server vendor to concentrate on system level functionalities while the developer can concentrate more on only the business logic for the domain specific application.
1. Reusable Components
Each EJB is a reusable building block. An EJB can be reused by assembling them in several different
applications. For each application, making simple changes in deployment descriptor without the source code can customize its 28 behavior with the underlying services.
2. Portable
EJB use Java language, which is portable across multiple platforms. The components can run on any platform and are completely portable
across any vendor’s EJB-compliant application server. The EJB environment automatically maps the component to the
underlying vendor-specific infrastructure services. 3. Fast building of Application
The EJB architecture simplifies building complex enterprise applications.
With the component-based EJB architecture, the development, enhancing the functionalities and maintenance of complex enterprise applications becomes easier.
With its clear definition of roles and well defined interfaces, the EJB architecture promotes and supports team-based development and lessens the demands on individual developers.
Q.5(c) Write a session bean code specification that calculates compound
interest. Assume the principal, terms and rate of interest is entered bythe user and the input is passed through a servlet.
[5]
(A) //index.html < html > < body > < form method = “post” action = “test” >, Principal amount < input type = “text” name = “a” value = “ “ Size = “10” >, No of terms
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< input type = “text” name = “b” value = “ “ Size = “10” >, Rate of interest < input type = “text” name = “c” value = “ “ Size = “10” >, < input type = “submit” value = “Compound Interest”> < / form > < / body > </ html > // test.java (servlet) import javax . servlet . *; import javax . servlet . http . * ; import java . io. * ; public class test extends HttpServlet < public void dopost (HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException < res.setContentType (“text/html”); PrintWriter pw = res.getwriter) ; int i = Integer.parseInt (req.getParameter (“0”)); int n = Integer.parseInt (req.getParameter (“b”)); int r = Integer.parseInt (req.getParameter (“c”)); compound C = new Compound ( ); pw.printInt compound intrest. t<); pw.close ( ); } } // compound.java (Session bean) import javax.bean.*; @ Stateless public class compound { public double interest (int p, int n, int r) { double 2 = P * Math.pow (1 + r/100, n) P ; return 2 ; }
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Q.5(d) Write a session bean code specification that calculates compoundinterest. Assume the principal, terms and rate of interest isentered by the user and the input is passed through a servlet.
[5]
(A) import java.rmi.RemoteException; import javax.ejb.SessionBean; import javax.ejb.SessionContext; /** This class contains the implementation for the `calculateCompoundInterest'
method exposed by this Bean. It includes empty method bodies for the methods prescribe by the SessionBean interface; these don't need to do anything in this simple example.
*/
public class InterestBean implements SessionBean { /** Calculates the compound interest on the sum `principle', with interest rate
per period `rate' over `periods' time periods. This method also prints a message to standard output; this is picked up by the EJB server and logged. In this way we can demonstrate that the method is actually being executed on the server, rather than the client.
*/ public double calculateCompoundInterest(double principle, double rate, double periods) { System.out.println ("Someone called `calculateCompoundInterest!'"); return principle * Math.pow(1+rate, periods) - principle; } Q.6 Attempt the following (any TWO) [10]Q.6(a) Explain the different roles of Action in struts framework. [5](A) Action is the heart and soul of the Struct framework. It processes input and
interacts with other layers of the application. [1 Marks]
Roles of Action [4 Marks] 1. Perform As a model
Action performs as a Model by encapsulating the actual work to be done for a given request based on the input parameters.
Encapsulation is done using the execute() method. The code spec inside this method should only hold the business logic to serve a Request.
2. Serves as a Data Carrier Action serves as a data carrier from Request to the View. Action being the Model component of the framework carries the
data around.. The data that it requires is held locally which makes it easy to
access using JavaBeans properties during the actual execution of the business logic.
3. Helps determine the results
Action determines the Result that will render the View that will be returned in the request’s response. This is achieved by returning a control string that selects the result that should be rendered.
4. Single Or Multiple Results The most basic action performs the required task and always results
a single result. An action can also return different results depending on the complexity of the –business logic.
Q.6(b) Explain in brief MVC architecture with help of suitable diagram. [5](A)
MVC architecture has three different sections – i) Model ii) View iii) Controller
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In the MVC design pattern, the application flow is mediate by a Controller. The controller delegates HTTP request to an appropriate handler. A Handler is a set of logic that is used to process the request. In the
Strct framework, the handlers are called as Actions. The handlers are tied to a Model and each handler acts as an adapter or
bridge, between the Request and the Model. A handler or action may use one or more JavaBeans or EJBs to perform the actual business logic.
The Action gets any information out of the request necessary to perform the desired business logic and then passes it to the JavaBean or EJB.
Technically : Using web based data entry form information is submitted to the server. The controller receives such requests and to serve them calls the
appropriate handler i.e. Action. Action passes the request by interacting with the application specific
model code. Model returns a result to inform the Controller which output page to be
sent as a response. Information is passes between Model and View in the form of special
JavaBeans. A powerful Tag Library allows reading and writing the content of these
beans from the presentation layer without the need for any embedded java code spec.
From the development point of view, structs :
> Provides a Controller > Facilitates writing templates to form the View i.e. the presentation layer. > Facilitates writing the Model code specs. A central configuration file called struts.xml binds all these [Model,
View, Controller] together. Q.6(c) Explain web.xml and struts.xml files. [5]
(A) Web.xml [2 ½ Marks] the web.xml web application descriptor file represents the core of the
java web application, so it is appropriate that it is also part of the core of Struct Framework
in this file, Struts defines I ts Filedispatcher, the Servler filter class that initializes the Struts framework and handles all requests. Vidy
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This filtr can contain initialization parameters that affect what, if any, additional configuration files are loaded and how the framework should behave.
Struts also provides an ActionContextCleanUp class that handles special cleanup tasks when other filters need access to an initialized Struts framework.
Key Initialization Parameters : Config - a comma delimited list of XML configuration files to load. actionPac scan for actkages – a comma delimited list of Java packages
Actions. configProviders - a comma delimited list of Java classes that implement
the ConfigurationProvider interface that should be used for building the configuration.
loggerFactory – The class name of the LoggerFactory implementation. * - any other parameter are treated as framework constants. Struts.xml [2 ½ Marks] The Struts framework uses this configuration file to initialize its own
resources. These resources include – Interceptors that can preprocess and postprocess a request. Action classes that can call business logic and data access code. Results that can prepare views using JavaServer Pages, Velocity and
FreeMarker templates. The struts.xml is the core configuration file for the framework and it
should be present in the class path of web application. This file allows to break big struts.xml file into cmall files and
configuration files to be included as needed. Example <struts> ----- ----- <include file = “file1.xml” /> <include file = “file2.xml” /> ---- ---- </struts>
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Vidyalankar : T.Y. B.Sc. (IT) – Adv. Java
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Q.6(d) Explain the architecture of hibernate framework in details. [5](A)
JTA – Java Transaction API JDBC – Java Database Connectivity JNDI – Java Naming and Directory Interface
Configuration Object [4 Marks] This object represents a configuration or properties file for hibernate.
It is usually created once during application initialization. The configuration object reads the properties to establish a database
connection. A Configuration object is spawned to create a SessionFactory.
Session Factory The SessionFactory is created with the help of a Configuration object
during the application start up. It serves as a factory for spawning Session objects when required.
Typically, it is crated once and kept alive for later use. The applications that require interacting with multiple databses, multiple
SessionFactory objects are created.
Session Session objects are lightweight and inexpensive to create. They provide
the main interface to perform actual database operations.
[1 Marks]
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All the persistent objects are saved and retrieved with the help of a Session object.
Typically, session objects are created as needed and destroyed when not required.
Transaction A transaction represents a unit of work the database. Any kind of modifications initiated via the session object are placed
within a transaction. A session object helps creating a Transaction object.
Transaction objects are used for a short time and are closed by either committing or rejecting.
Query Persistent objects are retrieved using a Query object. Query objects allow using SQL or Hibernate Query Language (HQL)
queries to retrieve the actual data from the database and create objects.
Criteria Persistent objects can also be retrieved using a Criteria object. Criteria uses an object/method means of constructing and executing a
request to retrieve objects. Q.7 Attempt the following (any THREE) [15]Q.7(a) What are the different types of layout in Java? Explain
Grid Layout [2 Marks] A GridLayout object places components in a grid of cells. Each component takes all the available space within its cell, and each cell is exactly the same size. If the GridLayoutDemo window is resized, the GridLayout object changes the cell size so that the cells are as large as possible, given the space available to the container.
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Vidyalankar : T.Y. B.Sc. (IT) – Adv. Java
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Layout Design [1 Marks]
Sample Program or Code snippet [1 marks] import java.awt.*; import java.applet.*; . /* <applet code=”SimpleKey” width=300 height=300> </applet> */ public class gridLayoutDemo extends Applet { static final int n = 4; public void init() { setLayout (new GridLayout(n , n)); setFont (new Font(“SansSerif”, Font.BOLD, 24)); for(int i=0; i<n; i++) { for(j=0; j<n; j++) { int k =i*n+j; if (k > 0) add(new Button (“ ”+ k)); } } } }
Q.7(b) Explain how Progress Bar as a component can be useful in swing. [5](A) A user can be made aware about the software loading process by viewing how
much loading process is complete and how much is to be completed.
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This type of software loading progress can be shown using the Java component ProgressBar.
It is a simple component , just a rectangle that is partially filled with color to indicate the progress of a software loading operation.
By default, progress is indicated by a string “n%”. [2 Marks]
A ProgressBar Example [3 Marks] import java.awt.BorderLayout; import java.awt.Container; import javax.swing.BorderFactory; import javax.swing.JFrame; import javax.swing.JProgressBar; import javax.swing.border.Border; public class ProgressSample { public static void main(String args[]) { JFrame f = new JFrame("JProgressBar Sample"); f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); Container content = f.getContentPane(); JProgressBar progressBar = new JProgressBar(); progressBar.setValue(25); progressBar.setStringPainted(true); Border border = BorderFactory.createTitledBorder("Reading..."); progressBar.setBorder(border); content.add(progressBar, BorderLayout.NORTH); f.setSize(300, 100); f.setVisible(true); } }
Q.7(c) Write a servlet application to find the sum of digits of the number
response.setContentType("text/html;charset=UTF-8"); PrintWriter out = response.getWriter(); String n1=request.getParameter("t1"); //String n1="10"; int n2 = Integer.parseInt(n1);
try {
int i=0; int sum=0,tot, rem; int no=1; while (n2>0) { rem = n2 % 10; tot = tot+ rem n2=n2/10; } out.println(tot);
} finally {
out.close(); }
}
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Q.7(d) Explain the 2-tier and 3 t-tier models of JDBC. [5](A) [Explanation of 2-tier 2 marks, Explanation of 3-tier 2 marks,
Diagrams 1 mark] Two-tier and Three-tier Processing Models The JDBC API supports both two-tier and three-tier processing models
for database access. Two –tier Model
Fig. 1: Two-tier Architecture for Data Access.
In the two-tier model, a Java applet or application talks directly to the data source.
This requires a JDBC driver that can communicate with the particular data source being accessed.
A user's commands are delivered to the database or other data source, and the results of those statements are sent back to the user.
The data source may be located on another machine to which the user is connected via a network. This is referred to as a client/server configuration, with the user's machine as the client, and the machine housing the data source as the server.
The network can be an intranet, which, for example, connects employees within a corporation, or it can be the Internet.
Three –Tier Model In the three-tier model, commands are sent to a "middle tier" of
services, which then sends the commands to the data source. The data source processes the commands and sends the results back to
the middle tier, which then sends them to the user. MIS directors find the three-tier model very attractive because the
middle tier makes it possible to maintain control over access and the kinds of updates that can be made to corporate data.
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Another advantage is that it simplifies the deployment of applications. Finally, in many cases, the three-tier architecture can provide performance advantages.
Fig. 2: Three-tier Architecture for Data Access. Q.7(e) Explain with suitable example <navigation-rule> element of faces-
config.xml file JSF. [5]
(A) [Explanation of all elements 4 marks, Program 1 marks]
<navigation-rule>
</navigation-rule> The <navigation-rule> element represents an individual decision rule. This rule is accessed when the default Navigation Handler is implemented. This rule helps make decisions on what view to display next, based on the View ID being processed.
The <from-view-id> Element <from-view-id> /index.xhtml </from-view-id> The <from-view-id> element contains the view identifier bound to the view for which the containing navigation rule is relevant. If no <from-view> element is specified, then this rule automatically applies to navigation decisions on all views. Since this element is not specified, a value of “*” is assumed, which means that this navigation rule applies to all views.
The <navigation-case> Element <navigation-case>
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- - - - - -
</navigation-case> The <navigation-case> element describes a specific combination of conditions that must match, for this case to be executed. It also describes the view id of the component tree that should be selected next.
The <from-outcome> Element <from-outcome> login </from-outcome> The <from-outcome> element contains a logical outcome string. This string is returned by the execution of an application action method via an actionRef property of a UICommand component. If this element is specified, then this rule is relevant only if the outcome value matches this element’s value. If this element is not specified, then this rule is relevant no matter what the outcome value was. The <to-view-id> Element <to-view-id> / Welcome.xhtml </to-view-id> The <to-view-id> element contains the view identifier of the next view that must be displayed when this navigation rule is matched. Example <navigation-rule> <from-view-id>/pages/inputname.jsp</from-view-id> <navigation-case> <from-outcome>sayHello</from-outcome> <to-view-id>/pages/greeting.jsp</to-view-id> </navigation-case> <navigation-case> <from-outcome>sayGoodbye</from-outcome> <to-view-id>/pages/goodbye.jsp</to-view-id> </navigation-case> </navigation-rule> This code specifies that view /pages/inputname.jsp has two outputs,
sayHello and sayGoodbye, associated with particular pages.
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Vidyalankar : T.Y. B.Sc. (IT) – Adv. Java
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Q.7(f) Explain the importance of mapping and show the creation of mappingfile in hibernate framework.
[5]
(A) [Importance – 2marks, Creation - 3 marks] Mapping Mapping is used to provide Hibernate with information to persist objects
to a relational database. Mapping files also provide support features such as creating the
database schema from a collection of mapping files. Creation of mapping file
In Hibernate, mapping a bean to a relational database is done by creating a mapping file in XML.
Hibernate mapping files are used to specify how your objects relate to database tables. To create basic mappings for properties and associations, i. e. generate .hbm.xml files, Hibernate Tools provide a basic wizard which you can display by selecting File → New → Hibernate XML mapping file. At first you will be asked to select a package or multiple individual classes to map. It is also possible to create an empty file: do not select any packages or classes and an empty .hbm file will be created in the specified location. Using the depth control option you can define the ependency depth used when choosing classes.
Hibernate XML Mapping File Wizard The next wizard page lists the mappings to be generated. You can see the Customers, Orders, Productlines and Products classes added under depth control driving.
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Mappings to be generated This wizard page display a preview of the generated .hbm files.
Preview Generated Mapping Files Clicking the Finish button creates the files.
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