Hosur road, 1km before Electronic City, Bengaluru Date : 4/10/17 Max Marks : 50. Subject & Code : JAVA and J2EE (10CS753) Section : A,B,C

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1 USN 1 P E PESIT Bangalore South Campus Hosur road, 1km before Electronic City, Bengaluru -100 Department of Computer Science And Engineering INTERNAL ASSESSMENT TEST II Date : 4/10/17 Max Marks : 50 Subject & Code : JAVA and J2EE (10CS753) Section : A,B,C Name of faculty : Ms. Neeta, Ms. Lakshmi NPR Time : 11:30 am to 1:00pm Scheme and Solutions 1. a) What is multithreading? Write a program to create multiple threads in java. 5M A multithreaded program contains two or more parts that can run concurrently. Each part of such a program is called a thread, and each thread defines a separate path of execution. class NewThread implements Runnable { String name; // name of thread Thread t; NewThread(String threadname) { name = threadname; t = new Thread(this, name); System.out.println("New thread: " + t); t.start(); // Start the thread // This is the entry point for thread. public void run() { for(int i = 5; i > 0; i--) {

2 System.out.println(name + ": " + i); Thread.sleep(1000); catch (InterruptedException e) { System.out.println(name + "Interrupted"); System.out.println(name + " exiting."); class MultiThreadDemo { public static void main(string args[]) { new NewThread("One"); // start threads new NewThread("Two"); new NewThread("Three"); // wait for other threads to end Thread.sleep(10000); catch (InterruptedException e) { System.out.println("Main thread Interrupted"); System.out.println("Main thread exiting."); Output: New thread: Thread[One,5,main] New thread: Thread[Two,5,main] New thread: Thread[Three,5,main]

3 b) Write a java program that demonstrates thread priorities by extending the Thread class. 5M class clicker extends Thread { long click = 0; Thread t; private volatile boolean running = true; public clicker(int p) { t = new Thread(this); t.setpriority(p); public void run() { while (running) { click++; public void stop() { running = false; public void start() { t.start(); class HiLoPri { public static void main(string args[]) { Thread.currentThread().setPriority(Thread.MAX_PRIORITY); clicker hi = new clicker(thread.norm_priority + 2); clicker lo = new clicker(thread.norm_priority - 2); lo.start();

4 hi.start(); Thread.sleep(10000); catch (InterruptedException e) { System.out.println("Main thread interrupted."); lo.stop(); hi.stop(); // Wait for child threads to terminate. hi.t.join(); lo.t.join(); catch (InterruptedException e) { System.out.println("InterruptedException caught"); System.out.println("Low-priority thread: " + lo.click); System.out.println("High-priority thread: " + hi.click); Output: Low-priority thread: High-priority thread: What is producer-consumer problem? Explain the solution for producer-consumer problem with java program. 10M

5 class Q { int n; boolean valueset = false; synchronized int get() { while(!valueset) wait(); catch(interruptedexception e) { System.out.println("InterruptedException caught"); System.out.println("Got: " + n); valueset = false; notify(); return n; synchronized void put(int n) { while(valueset) wait(); catch(interruptedexception e) { System.out.println("InterruptedException caught"); this.n = n; valueset = true;

6 System.out.println("Put: " + n); notify(); class Producer implements Runnable { Q q; Producer(Q q) { this.q = q; new Thread(this, "Producer").start(); public void run() { int i = 0; while(true) { q.put(i++); class Consumer implements Runnable { Q q; Consumer(Q q) { this.q = q; new Thread(this, "Consumer").start(); public void run() { while(true) { q.get();

7 class PCFixed { public static void main(string args[]) { Q q = new Q(); new Producer(q); new Consumer(q); System.out.println("Press Control-C to stop."); 3. What is the need for synchronization? Explain with example how synchronization is implemented in Java. 10M When two or more threads need access to a shared resource, they need some way to ensure that the resource will be used by only one thread at a time. The process by which this is achieved is called synchronization. class Callme { void call(string msg) { System.out.print("[" + msg); Thread.sleep(1000); catch(interruptedexception e) { System.out.println("Interrupted"); System.out.println("]"); class Caller implements Runnable { String msg; Callme target;

8 Thread t; public Caller(Callme targ, String s) { target = targ; msg = s; t = new Thread(this); t.start(); // synchronize calls to call() public void run() { synchronized(target) { // synchronized block target.call(msg); class Synch { public static void main(string args[]) { Callme target = new Callme(); Caller ob1 = new Caller(target, "Hello"); Caller ob2 = new Caller(target, "Synchronized"); Caller ob3 = new Caller(target, "World"); // wait for threads to end ob1.t.join(); ob2.t.join(); ob3.t.join();

9 catch(interruptedexception e) { System.out.println("Interrupted"); 4. a)give and explain the J2EE Multi-tier architecture. 6M CLIENT TIER : Client tier consists of programs that interact with the user. It prompts the user for input and then convert the user s response into requests that are forwarded to software on a component that processes the request and returns results to the client program Web tier provides internet functionality to j2ee application.components that operate on web tier use http to receive requests and send response to client. The EJB tier contains EJB server,which is the object server that stores and manages enterprise java beans.this tier provides concurrency, scalability and fault tolerance. EIS(enterprise information system) tier is the j2ee architectures connectivity to resources that are not part of j2ee such as legacy systems,dbms. b) Write a note on JDBC Drivers. 4M (i)jdbc-odbc Bridge, plus ODBC driver (Type 1) Simplest

10 JDBC methods -> Translate JDBC methods to ODBC methods -> ODBC to native methods -> Native methods API (ii)native-api, partly Java driver (Type 2) JDBC methods -> Map JDBC methods to native methods (calls to vendor library) -> Native methods API (vendor library) (iii)jdbc-net, pure Java driver (Type 3) JDBC methods -> Translate to Native API methods through TCP/IP network -> Native API methods (ivnative-protocol, pure Java driver (Type 4) Java methods -> Native methods in Java 5. Describe various steps of JDBC process with code snippets. 10M 1) Class.forName( sun.jdbc.odbc.jdbcodbcdriver ); The forname() method can throw a ClassNotFoundException if the driver class is not found. Hence, this function call should be in a try-catch block. The above statement loads the JDBC driver and takes care of any initialization that needs to be done 2.)Creating a connection to a data source Connection object represents an established connection to a particular data source A connection object can also be used to query the data source (data and meta data) Different versions of getconnection() method contained in the DriverManager class that returns a connection object: Connection myconn = DriverManager.getConnection(source); 3.)Statement objects are created by calling the createstatement() method of a valid connection object Used to execute an SQL query by calling the executequery() method of Statement object The SQL query string is passed as argument to the executequery() method Statement mystatement = myconn.createstatement(); 4.) The result of executing the query is returned as on object of type ResultSet ResultSet myresults = mystatement.executequery( select * from authors ); 5.)close the connection to database.

11 Ex:import java.sql.*; import java.util.*; class ConnectionToDB { public void getconnectedtodb(string drivername) { System.out.println(driverName); Class.forName(driverName); System.out.println("Hello"); Connection con = DriverManager.getConnection("jdbc:mysql://localhost/students","root","root123"); if(con!= null) System.out.println("Success"); Statement st = con.createstatement(); ResultSet rs = st.executequery("select * from STUDENT"); System.out.println("USN\t\tNAME\t\tADDRESS"); while(rs.next()) { String usn = rs.getstring(2); String name = rs.getstring(1); String addr = rs.getstring(3); System.out.println(usn+"\t\t"+name+"\t\t"+addr+"\t"); rs.close(); st.close(); con.close(); catch(classnotfoundexception e1) {

12 System.out.println(e1); catch(sqlexception e2) { System.out.println(e2); class DBDemo { public static void main(string a[]) { String dname = "com.mysql.jdbc.driver"; ConnectionToDB cdb = new ConnectionToDB(); cdb.getconnectedtodb(dname); 6. Write a note on the following : i) Delegation Event Model 5M The modern approach to handling events is based on the delegation event model, which defines standard and consistent mechanisms to generate and process events. Its concept is quite simple: a source generates an event and sends it to one or more listeners. In this scheme, the listener simply waits until it receives an event. Once an event is received, the listener processes the event and then 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. A user interface element is able to delegate the processing of an event to a separate piece of code. In the delegation event model, listeners must register with a source in order to receive an event notification. This provides an important benefit: notifications are sent only to listeners that want to receive them. This is a more efficient way to handle events than the design used by the old Java 1.0 approach. Previously, an event was propagated up the containment hierarchy until it was handled by a component. This required components to receive events that they did not process, and it wasted valuable time. The delegation event model eliminates this overhead. ii) Adapter classes 5M Java provides a special feature, called an adapter class, that can simplify the creation of event handlers in certain situations. An adapter class provides an empty implementation of all methods in an event listener interface. Adapter classes are useful when you want to receive and process only some of the events that are handled by a particular event listener interface. You can define a new class to act as an event listener by extending one of the adapter classes and implementing only those events in which you are interested.

13 Adapter Class ComponentAdapter ContainerAdapter FocusAdapter KeyAdapter MouseAdapter MouseMotionAdapter WindowAdapter Listener Interface ComponentListener ContainerListener FocusListener KeyListener MouseListener MouseMotionListener WindowListener 7. a)create a Simple Banner Applet that scrolls a message across applet window.5m import java.awt.*; import java.applet.*; /* <applet code="simplebanner" width=300 height=50> </applet> */ public class SimpleBanner extends Applet implements Runnable { String msg = " A Simple Moving Banner."; Thread t = null; int state; boolean stopflag; // Set colors and initialize thread. public void init() { setbackground(color.cyan); setforeground(color.red);

14 // Start thread public void start() { t = new Thread(this); stopflag = false; t.start(); // Entry point for the thread that runs the banner. public void run() { char ch; // Display banner for( ; ; ) { repaint(); Thread.sleep(250); ch = msg.charat(0); msg = msg.substring(1, msg.length()); msg += ch; if(stopflag) break; catch(interruptedexception e) { // Pause the banner. public void stop() {

15 stopflag = true; t = null; // Display the banner. public void paint(graphics g) { g.drawstring(msg, 50, 30); b) Write java and html code to pass parameters to applet window 5M import java.awt.*; import java.applet.*; /* <applet code="paramdemo" width=300 height=80> <param name=fontname value=courier> <param name=fontsize value=14> <param name=leading value=2> <param name=accountenabled value=true> </applet> */ public class ParamDemo extends Applet{ String fontname; int fontsize; float leading; boolean active; // Initialize the string to be displayed. public void start() { String param;

16 fontname = getparameter("fontname"); if(fontname == null) fontname = "Not Found"; param = getparameter("fontsize"); if(param!= null) // if not found fontsize = Integer.parseInt(param); else fontsize = 0; catch(numberformatexception e) { fontsize = -1; param = getparameter("leading"); if(param!= null) // if not found leading = Float.valueOf(param).floatValue(); else leading = 0; catch(numberformatexception e) { leading = -1; param = getparameter("accountenabled"); if(param!= null) active = Boolean.valueOf(param).booleanValue();

17 // Display parameters. public void paint(graphics g) { g.drawstring("font name: " + fontname, 0, 10); g.drawstring("font size: " + fontsize, 0, 26); g.drawstring("leading: " + leading, 0, 42); g.drawstring("account Active: " + active, 0, 58); 8. Write an applet program that shows the pressed or released status of each key in status window and displays text and special keys in applet window. 10M import java.awt.*; import java.awt.event.*; import java.applet.*; /* <applet code="keyevents" width=300 height=100> </applet> */ public class KeyEvents extends Applet implements KeyListener { String msg = ""; int X = 10, Y = 20; // output coordinates public void init() { addkeylistener(this); public void keypressed(keyevent ke) { showstatus("key Down");

18 public void keyreleased(keyevent ke) { showstatus("key Up"); public void keypressed(keyevent ke) { showstatus("key Down"); int key = ke.getkeycode(); switch(key) { case KeyEvent.VK_F1: msg += "<F1>"; break; case KeyEvent.VK_F2: msg += "<F2>"; break; case KeyEvent.VK_F3: msg += "<F3>"; break; case KeyEvent.VK_PAGE_DOWN: msg += "<PgDn>"; break; case KeyEvent.VK_PAGE_UP: msg += "<PgUp>"; break; case KeyEvent.VK_LEFT: msg += "<Left Arrow>";

19 break; case KeyEvent.VK_RIGHT: msg += "<Right Arrow>"; break; repaint(); public void keyreleased(keyevent ke) { showstatus("key Up"); public void keytyped(keyevent ke) { msg += ke.getkeychar(); repaint(); // Display keystrokes. public void paint(graphics g) { g.drawstring(msg, X, Y);

04-Java Multithreading

04-Java Multithreading Join Google+ community http://goo.gl/u7qvs You can ask all your doubts, questions and queries by posting on this G+ community during/after webinar http://openandroidlearning.org