Notes

//myfirstjavaprogram.java
public class myfirstjavaprogram{
public static void main(String args[]){
System.out.println("My name is barry allen");
}
}


Addition of Elements of an Array using Dynamic Array
import java.util.ArrayList;
import java.util.Scanner;

public class DynamicArrayAddition {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
ArrayList<Integer> numbers = new ArrayList<>(); // Dynamic Array

System.out.println("Enter numbers (enter -1 to stop):");

while (true) {
int num = input.nextInt();
if (num == -1) break; // Stop input when -1 is entered
numbers.add(num); // Add element to the dynamic array
}

// Calculate sum
int sum = 0;
for (int num : numbers) {
sum += num;
}

// Display results
System.out.println("Numbers entered: " + numbers);
System.out.println("Sum of the elements: " + sum);

input.close();
}
}




Experiment 3: Program to Demonstrate Constructor Overloading, Method
Overloading and Operator Overloading .
class OverloadDemo {
int a, b;
OverloadDemo() {
this.a = 0;
this.b = 0;
}
OverloadDemo(int x, int y) {
this.a = x;
this.b = y;
}
void add() {
System.out.println("Sum (default values): " + (a + b));
}
void add(int x, int y) {
System.out.println("Sum of given numbers: " + (x + y));
}
void add(double x, double y) {
System.out.println("Sum of doubles: " + (x + y));
}
OverloadDemo add(OverloadDemo obj) {
OverloadDemo temp = new OverloadDemo();

temp.a = this.a + obj.a;
temp.b = this.b + obj.b;

return temp;
}
void display() {
System.out.println("Values: a = " + a + ", b = " + b);
}
}
public class OverloadingExample {
public static void main(String[] args) {
OverloadDemo obj1 = new OverloadDemo();
OverloadDemo obj2 = new OverloadDemo(10, 20);

System.out.println("nConstructor Overloading:");
obj1.display();
obj2.display();
System.out.println("nMethod Overloading:");
obj2.add();
obj2.add(15, 25);
obj2.add(5.5, 4.5);
System.out.println("nOperator Overloading Simulation:");
OverloadDemo obj3 = new OverloadDemo(5, 7);
OverloadDemo obj4 = new OverloadDemo(3, 6);
OverloadDemo result = obj3.add(obj4);
System.out.print("After addition: ");
result.display();
}
}



Experiment 4: Program to show the use of Private, Protected, Public and
Default Access Specifiers.

package accessdemo;
class Parent {
private int privateVar = 10;
protected int protectedVar = 20;
public int publicVar = 30;
int defaultVar = 40;
void display() {
System.out.println("Inside Parent Class:");
System.out.println("Private Variable: " + privateVar);
System.out.println("Protected Variable: " + protectedVar);
System.out.println("Public Variable: " + publicVar);
System.out.println("Default Variable: " + defaultVar);
}
class Child extends Parent {
void show() {
System.out.println("nInside Child Class:");
System.out.println("Protected Variable: " + protectedVar);
System.out.println("Public Variable: " + publicVar);
System.out.println("Default Variable: " + defaultVar);
}
}
public class AccessSpecifierDemo {
public static void main(String[] args) {
Parent parent = new Parent();
System.out.println("Inside Main Method:");
System.out.println("Protected Variable: " + parent.protectedVar);
System.out.println("Public Variable: " + parent.publicVar);
System.out.println("Default Variable: " + parent.defaultVar);
Child child = new Child();
child.show();
}
}


Experiment 5: Demonstrate and Use Packages in Java.
// File: com/example/MyPackage.java package com.example;
package mypackage;
public class MyClass {
public void displayMessage() {
System.out.println("Hello from MyClass inside mypackage!");
}
}
// File: Main.java
import mypackage.MyClass;
public class Main {
public static void main(String[] args) {
MyClass obj = new MyClass();
obj.displayMessage();
}
}


Experiment 6: Demonstrate and Use Different Types of Inheritance in Java

// InheritanceDemo.java
class Parent {
void show() {
System.out.println("This is Parent class");
}
}
// --- Single Inheritance ---
class Child extends Parent {
void display() {
System.out.println("This is Child class");
}
}
// --- Multilevel Inheritance ---
class Grandparent {
void grandparentMethod() {
System.out.println("This is Grandparent class");
}
}
class Parent2 extends Grandparent {
void parentMethod() {
System.out.println("This is Parent class");
}
}
class Child2 extends Parent2 {
void childMethod() {
System.out.println("This is Child class");
}
}
// --- Multiple Inheritance (Using Interfaces) ---
interface A {
void methodA();
}
interface B {
void methodB();
}
class C implements A, B {
public void methodA() {
System.out.println("Method A from Interface A");
}
public void methodB() {
System.out.println("Method B from Interface B");
}
}
// --- Hierarchical Inheritance ---
class Child1 extends Parent {
void displayChild1() {
System.out.println("This is Child1 class");
}
}
class Child3 extends Parent {
void displayChild3() {
System.out.println("This is Child3 class");
}
}

public class InheritanceDemo {
public static void main(String[] args) {

// Single Inheritance
System.out.println("Single Inheritance:");
Child obj1 = new Child();
obj1.show();
obj1.display();
// Multilevel Inheritance
System.out.println("nMultilevel Inheritance:");
Child2 obj2 = new Child2();
obj2.grandparentMethod();
obj2.parentMethod();
obj2.childMethod();

// Multiple Inheritance
System.out.println("nMultiple Inheritance:");
C obj3 = new C();
obj3.methodA();
obj3.methodB();
// Hierarchical Inheritance
System.out.println("nHierarchical Inheritance:");
Child1 obj4 = new Child1();
obj4.show();
obj4.displayChild1();
Child3 obj5 = new Child3();
obj5.show();
obj5.displayChild3();
}
}

Experiment 7: Demonstrate Exception Handling in Java.
import java.util.Scanner;
public class ExceptionHandlingExample {
public static void main(String[] args) {
Scanner input = new Scanner(System.in)
try {
System.out.print("Enter a number: ");
int num1 = input.nextInt();
System.out.print("Enter another number: ");
int num2 = input.nextInt();
int result = num1 / num2;
System.out.println("Result: " + result);
} catch (ArithmeticException e) {
System.out.println("Error: Division by zero is not allowed.");
} catch (Exception e) {
System.out.println("Error: An unexpected error occurred.");
} finally {
input.close();
System.out.println("Program execution completed.");
}
}



LAB 2
Experiment 1: User Interface using Swing

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class SwingFormExample {
public static void main(String[] args) {
JFrame frame = new JFrame("Swing Form Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(400, 400);
JPanel panel = new JPanel();
panel.setLayout(new GridLayout(8, 2, 10, 10));
JLabel nameLabel = new JLabel("Name:");
JTextField nameField = new JTextField();
JLabel ageLabel = new JLabel("Age:");
JTextField ageField = new JTextField();
JLabel addressLabel = new JLabel("Address:");
JTextField addressField = new JTextField();
JLabel contactLabel = new JLabel("Contact:");
JTextField contactField = new JTextField();
JLabel emailLabel = new JLabel("Email:");
JTextField emailField = new JTextField();
JLabel genderLabel = new JLabel("Gender:");
String[] genders = { "Male", "Female", "Other" };
JComboBox<String> genderComboBox = new JComboBox<>(genders);
JLabel countryLabel = new JLabel("Country:");
JTextField countryField = new JTextField();
JButton submitButton = new JButton("Submit");
JTextArea outputArea = new JTextArea(5, 30);
outputArea.setEditable(false);
submitButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
String name = nameField.getText();
String age = ageField.getText();
String address = addressField.getText();
String contact = contactField.getText();
String email = emailField.getText();
String gender = (String) genderComboBox.getSelectedItem();
String country = countryField.getText();
String output = String.format("Name: %snAge: %snAddress: %snContact: %snEmail: %snGender:
%snCountry: %s",
name, age, address, contact, email, gender, country);
outputArea.setText(output);
}
});
panel.add(nameLabel);
panel.add(nameField);
panel.add(ageLabel);
panel.add(ageField);
panel.add(addressLabel);
panel.add(addressField);
panel.add(contactLabel);
panel.add(contactField);
panel.add(emailLabel);
panel.add(emailField);
panel.add(genderLabel);
panel.add(genderComboBox);
panel.add(countryLabel);
panel.add(countryField);
panel.add(submitButton);
panel.add(new JScrollPane(outputArea));
frame.add(panel);
frame.setVisible(true);
}
}



LAB 3
Experiment 1: Event Handling in Java

import javax.swing.*;
import java.awt.event.*;
public class EventHandlingExample {
public static void main(String[] args) {
JFrame frame = new JFrame("Event Handling Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(300, 200);
JButton button = new JButton("Click Me");
JLabel label = new JLabel("Button not clicked yet", SwingConstants.CENTER);
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
label.setText("Button clicked!");
}
});
frame.setLayout(new java.awt.BorderLayout());
frame.add(button, java.awt.BorderLayout.SOUTH);
frame.add(label, java.awt.BorderLayout.CENTER);
frame.setVisible(true);
}
}


LAB 4
Experiment 1: CRUD Operations in JAVA

import java.util.*;
class Student {
int id;
String name;
String address;
Student(int id, String name, String address) {
this.id = id;
this.name = name;
this.address = address;
}
}
public class StudentCRUD {
static Scanner sc = new Scanner(System.in);
static List<Student> students = new ArrayList<>();
public static void main(String[] args) {
int choice;
do {
System.out.println("nMenu:");
System.out.println("1. Create");
System.out.println("2. Read");
System.out.println("3. Update");
System.out.println("4. Delete");
System.out.println("5. Exit");
System.out.print("Enter your choice: ");
choice = sc.nextInt();
sc.nextLine(); // Consume newline
switch (choice) {
case 1:
create();
break;
case 2:
read();
break;
case 3:
update();
break;
case 4:
delete();
break;
case 5:
System.out.println("Exiting...");
break;
default:
System.out.println("Invalid choice! Try again.");
}
} while (choice != 5);
}
// Create Operation
public static void create() {
System.out.print("Enter ID: ");
int id = sc.nextInt();
sc.nextLine(); // Consume newline
System.out.print("Enter Name: ");
String name = sc.nextLine();
System.out.print("Enter Address: ");
String address = sc.nextLine();
students.add(new Student(id, name, address));
System.out.println("Student added successfully!");
}
// Read Operation
public static void read() {
System.out.println("nList of Students:");
if (students.isEmpty()) {
System.out.println("No students available.");
return;
}
for (Student student : students) {
System.out.println("ID: " + student.id + ", Name: " + student.name + ", Address: " + student.address);
}
}
// Update Operation
public static void update() {
System.out.print("Enter ID of student to update: ");
int id = sc.nextInt();
sc.nextLine(); // Consume newline
boolean found = false;
for (Student student : students) {
if (student.id == id) {
found = true;
System.out.print("Enter new Name: ");
student.name = sc.nextLine();
System.out.print("Enter new Address: ");
student.address = sc.nextLine();
System.out.println("Student details updated successfully!");
break;
}
}
if (!found) {
System.out.println("Student with ID " + id + " not found.");
}
}
// Delete Operation
public static void delete() {
System.out.print("Enter ID of student to delete: ");
int id = sc.nextInt();
boolean found = false;
Iterator<Student> iterator = students.iterator();
while (iterator.hasNext()) {
Student student = iterator.next();
if (student.id == id) {
iterator.remove();
found = true;
System.out.println("Student with ID " + id + " deleted successfully.");
break;
}
}
if (!found) {
System.out.println("Student with ID " + id + " not found.");
}
}
}


LAB 5
Experiment 1: To handle Http Request and Http Response in Servlet

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Login Page</title>
</head>
<body>
<center><% out.println("welcome to login page"); %></center>
<center><h1><u>Login Here</u></h1></center>
<center>
<div>
<form action="login" method="POST">
<table >
<tr>
<td>Username:<br><br></td>
<td><input type="text" name="username"><br><br></td>
</tr>
<tr>
<td>Password:<br><br></td>
<td><input type="text" name="password"><br><br></td>
</tr> <tr>
<td colspan="2" style="text-align: center"><input type="submit" value="submit"></td>
</tr>
</table>
</form>
</div>
</center>
</body>
</html>

Login.java:
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet(name = "login", urlPatterns = {"/login"})
public class login extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
try (PrintWriter out = response.getWriter()) {
String username = request.getParameter("username");
String password = request.getParameter("password");
if(username!= null && password!= null){
if(username.equals("admin") && password.equals("admin123")){
response.sendRedirect("welcome.jsp");
}else{
out.println("invalid username or password");
}
}else{
out.println("no empty fields, please");
}
}
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}
Welcome.jsp:
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>welcome Page</title>
</head>
<body>
<center><h1>welcome</h1></center>
<center><p>You are logged in.</p></center>
</body>
</html>


Experiment 2: To demonstrate RequestDispatcher in Servlet.

<form action="servlet1" method="post">
Name:<input type="text" name="userName"/><br/>
Password:<input type="password" name="userPass"/><br/>
<input type="submit" value="login"/>
</form>
Login.java
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class Login extends HttpServlet {
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
String n=request.getParameter("userName");
String p=request.getParameter("userPass");
if(p.equals("servlet"){
RequestDispatcher rd=request.getRequestDispatcher("servlet2");
rd.forward(request, response);
}
else{
out.print("Sorry UserName or Password Error!");
RequestDispatcher rd=request.getRequestDispatcher("/index.html");
rd.include(request, response);
}
}
}
WelcomeServlet.java
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class WelcomeServlet extends HttpServlet {
public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
String n=request.getParameter("userName");
out.print("Welcome "+n);
}
}
web.xml
<web-app>
<servlet>
<servlet-name>Login</servlet-name>
<servlet-class>Login</servlet-class>
</servlet>
<servlet>
<servlet-name>WelcomeServlet</servlet-name>
<servlet-class>WelcomeServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>Login</servlet-name>
<url-pattern>/servlet1</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>WelcomeServlet</servlet-name>
<url-pattern>/servlet2</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
</welcome-file-list>
</web-app>