Java-Slip-Solutions

Slip 1
==========
Question 1: Write a Java program using Multithreading to display all the alphabets between 'A' to 'Z' after every 2 seconds.
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public class AlphabetThread extends Thread {
    public void run() {
        for (char ch = 'A'; ch <= 'Z'; ch++) {
            System.out.println(ch);
            try {
                Thread.sleep(2000); // Sleep for 2 seconds
            } catch (InterruptedException e) {
                System.out.println("Thread interrupted.");
            }
        }
    }

    public static void main(String[] args) {
        AlphabetThread thread = new AlphabetThread();
        thread.start();
    }
}
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Question 2: Write a Java program to accept the details of Employee (Eno, EName, Designation, Salary) from a user and store it into the database. (Use Swing)
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import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.sql.*;

public class EmployeeForm extends JFrame {
    private JTextField enoField, enameField, desgField, salaryField;
    private JButton submitButton;

    public EmployeeForm() {
        setTitle("Employee Details");
        setLayout(new GridLayout(5, 2));
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        add(new JLabel("Employee No:"));
        enoField = new JTextField();
        add(enoField);

        add(new JLabel("Employee Name:"));
        enameField = new JTextField();
        add(enameField);

        add(new JLabel("Designation:"));
        desgField = new JTextField();
        add(desgField);

        add(new JLabel("Salary:"));
        salaryField = new JTextField();
        add(salaryField);

        submitButton = new JButton("Submit");
        add(submitButton);

        submitButton.addActionListener(e -> saveToDatabase());

        pack();
        setVisible(true);
    }

    private void saveToDatabase() {
        String eno = enoField.getText();
        String ename = enameField.getText();
        String desg = desgField.getText();
        String salary = salaryField.getText();

        try {
            Class.forName("org.postgresql.Driver");
            Connection con = DriverManager.getConnection("jdbc:postgresql://localhost:5432/testdb", "postgres", "password");
            String query = "INSERT INTO Employee (Eno, EName, Designation, Salary) VALUES (?, ?, ?, ?)";
            PreparedStatement ps = con.prepareStatement(query);
            ps.setString(1, eno);
            ps.setString(2, ename);
            ps.setString(3, desg);
            ps.setString(4, salary);
            ps.executeUpdate();
            JOptionPane.showMessageDialog(this, "Employee details saved successfully!");
            con.close();
        } catch (Exception ex) {
            JOptionPane.showMessageDialog(this, "Error: " + ex.getMessage());
        }
    }

    public static void main(String[] args) {
        new EmployeeForm();
    }
}
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Slip 2
==========
Question 1: Write a Java program to accept a string from the user and count the number of vowels in it.
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import java.util.Scanner;

public class VowelCounter {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter a string: ");
        String str = sc.nextLine().toLowerCase();
        int vowelCount = 0;

        for (char ch : str.toCharArray()) {
            if ("aeiou".indexOf(ch) != -1) {
                vowelCount++;
            }
        }

        System.out.println("Number of vowels: " + vowelCount);
        sc.close();
    }
}
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Question 2: Write a JSP program to accept two numbers from the user and display their sum.
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<html>
<body>
<h2>Sum of Two Numbers</h2>
<form method="post">
    Enter First Number: <input type="text" name="num1"><br>
    Enter Second Number: <input type="text" name="num2"><br>
    <input type="submit" value="Calculate">
</form>
<%
    String num1Str = request.getParameter("num1");
    String num2Str = request.getParameter("num2");
    if (num1Str != null && num2Str != null) {
        int num1 = Integer.parseInt(num1Str);
        int num2 = Integer.parseInt(num2Str);
        int sum = num1 + num2;
%>
<p>Sum: <%= sum %></p>
<% } %>
</body>
</html>
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Slip 3
==========
Question 1: Write a JSP program to display the details of Patient (PNo, PName, Address, Age, Disease) in tabular form on browser.
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<%@ page import="java.sql.*" %>
<html>
<body>
<h2>Patient Details</h2>
<table border="1">
    <tr>
        <th>PNo</th>
        <th>PName</th>
        <th>Address</th>
        <th>Age</th>
        <th>Disease</th>
    </tr>
    <%
        try {
            Class.forName("org.postgresql.Driver");
            Connection con = DriverManager.getConnection("jdbc:postgresql://localhost:5432/testdb", "postgres", "password");
            Statement stmt = con.createStatement();
            ResultSet rs = stmt.executeQuery("SELECT * FROM Patient");
            while (rs.next()) {
    %>
    <tr>
        <td><%= rs.getString("PNo") %></td>
        <td><%= rs.getString("PName") %></td>
        <td><%= rs.getString("Address") %></td>
        <td><%= rs.getInt("Age") %></td>
        <td><%= rs.getString("Disease") %></td>
    </tr>
    <%
            }
            con.close();
        } catch (Exception e) {
            out.println("Error: " + e.getMessage());
        }
    %>
</table>
</body>
</html>
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Question 2: Write a Java program to create LinkedList of String objects and perform the following...
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import java.util.LinkedList;
import java.util.Collections;

public class LinkedListDemo {
    public static void main(String[] args) {
        LinkedList<String> list = new LinkedList<>();

        // Adding elements
        list.add("Apple");
        list.add("Banana");
        list.add("Cherry");

        // i. Add element at the end
        list.addLast("Dragonfruit");
        System.out.println("After adding at end: " + list);

        // ii. Delete first element
        list.removeFirst();
        System.out.println("After deleting first element: " + list);

        // iii. Display in reverse order
        Collections.reverse(list);
        System.out.println("In reverse order: " + list);
    }
}
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Slip 8
==========
Question 1: Write a Java program to define a thread for printing text on output screen...
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public class TextThread extends Thread {
    private String text;
    private int times;

    public TextThread(String text, int times) {
        this.text = text;
        this.times = times;
    }

    public void run() {
        for (int i = 0; i < times; i++) {
            System.out.println(text);
            try {
                Thread.sleep(500); // Small delay for visibility
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    public static void main(String[] args) {
        TextThread t1 = new TextThread("COVID19", 10);
        TextThread t2 = new TextThread("LOCKDOWN2020", 20);
        TextThread t3 = new TextThread("VACCINATED2021", 30);

        t1.start();
        t2.start();
        t3.start();
    }
}
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Question 2: Write a JSP program to check whether a given number is prime or not...
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<html>
<body>
<h2>Prime Number Check</h2>
<form method="post">
    Enter Number: <input type="text" name="num">
    <input type="submit" value="Check">
</form>
<%
    String numStr = request.getParameter("num");
    if (numStr != null) {
        int num = Integer.parseInt(numStr);
        boolean isPrime = true;
        if (num <= 1) isPrime = false;
        for (int i = 2; i <= Math.sqrt(num); i++) {
            if (num % i == 0) {
                isPrime = false;
                break;
            }
        }
%>
<p style="color:red;">
<%
    if (isPrime) {
        out.println(num + " is a Prime Number");
    } else {
        out.println(num + " is not a Prime Number");
    }
%>
</p>
<% } %>
</body>
</html>
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Slip 12
===========
Question 1: Write a Java program to create an ArrayList of integers and find the maximum and minimum values.
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import java.util.ArrayList;
import java.util.Collections;

public class ArrayListMinMax {
    public static void main(String[] args) {
        ArrayList<Integer> numbers = new ArrayList<>();
        numbers.add(45);
        numbers.add(12);
        numbers.add(78);
        numbers.add(23);
        numbers.add(56);

        int max = Collections.max(numbers); // Auto-unboxing from Integer to int
        int min = Collections.min(numbers); // Auto-unboxing from Integer to int

        System.out.println("Maximum value: " + max);
        System.out.println("Minimum value: " + min);
    }
}

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Question 2: Write a Servlet program to accept a number from the user and check if it’s even or odd.
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<!-- evenodd.html -->
<html>
<body>
<h2>Check Even or Odd</h2>
<form action="EvenOddServlet" method="post">
    Enter Number: <input type="text" name="number"><br>
    <input type="submit" value="Check">
</form>
</body>
</html>

<!-- EvenOddServlet.java -->
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class EvenOddServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();

        String numStr = request.getParameter("number");
        int num = Integer.parseInt(numStr);

        out.println("<html><body>");
        out.println("<h2>Number Check</h2>");
        if (num % 2 == 0) {
            out.println("<p>" + num + " is Even</p>");
        } else {
            out.println("<p>" + num + " is Odd</p>");
        }
        out.println("</body></html>");
    }
}

<!--web.xml-->
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="https://jakarta.ee/xml/ns/jakartaee"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="https://jakarta.ee/xml/ns/jakartaee
                      https://jakarta.ee/xml/ns/jakartaee/web-app_6_0.xsd"
  version="6.0"
  metadata-complete="true">

<!-- EvenOdd -->
<servlet>
        <servlet-name>EvenOddServlet</servlet-name>
        <servlet-class>EvenOddServlet</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>EvenOddServlet</servlet-name>
        <url-pattern>/EvenOddServlet</url-pattern>
    </servlet-mapping>



    <error-page>
        <error-code>403</error-code>
        <location>/WEB-INF/jsp/403.jsp</location>
    </error-page>

</web-app>
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Slip 15
===========
Question 1: Write a Java program to display name and priority of a Thread.
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public class ThreadInfo {
    public static void main(String[] args) {
        Thread t1 = new Thread("Thread-1");
        Thread t2 = new Thread("Thread-2");

        t1.setPriority(Thread.MIN_PRIORITY); // 1
        t2.setPriority(Thread.MAX_PRIORITY); // 10

        System.out.println("Thread Name: " + t1.getName() + ", Priority: " + t1.getPriority());
        System.out.println("Thread Name: " + t2.getName() + ", Priority: " + t2.getPriority());
    }
}
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Question 2: Write a SERVLET program which counts how many times a user has visited a web page...
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import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class VisitCounterServlet extends HttpServlet {
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();

        Cookie[] cookies = request.getCookies();
        int visitCount = 0;

        if (cookies != null) {
            for (Cookie cookie : cookies) {
                if (cookie.getName().equals("visitCount")) {
                    visitCount = Integer.parseInt(cookie.getValue());
                }
            }
        }

        visitCount++;
        Cookie visitCookie = new Cookie("visitCount", String.valueOf(visitCount));
        response.addCookie(visitCookie);

        out.println("<html><body>");
        if (visitCount == 1) {
            out.println("<h2>Welcome! This is your first visit.</h2>");
        } else {
            out.println("<h2>You have visited this page " + visitCount + " times.</h2>");
        }
        out.println("</body></html>");
    }
}
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Slip 16
===========
Question 1: Write a Java program to create a TreeSet, add some colors...
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import java.util.TreeSet;

public class TreeSetDemo {
    public static void main(String[] args) {
        TreeSet<String> colors = new TreeSet<>();
        colors.add("Red");
        colors.add("Blue");
        colors.add("Green");
        colors.add("Yellow");

        System.out.println("Colors in ascending order: " + colors);
    }
}
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Question 2: Write a Java program to accept the details of Teacher...
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import java.sql.*;

public class TeacherDetails {
    public static void main(String[] args) {
        try {
            Class.forName("org.postgresql.Driver");
            Connection con = DriverManager.getConnection("jdbc:postgresql://localhost:5432/testdb", "postgres", "password");
            Statement stmt = con.createStatement();
            stmt.executeUpdate("CREATE TABLE IF NOT EXISTS Teacher (TNo INT, TName VARCHAR(50), Subject VARCHAR(50))");

            PreparedStatement ps = con.prepareStatement("INSERT INTO Teacher VALUES (?, ?, ?)");
            ps.setInt(1, 1); ps.setString(2, "John"); ps.setString(3, "JAVA"); ps.executeUpdate();
            ps.setInt(1, 2); ps.setString(2, "Alice"); ps.setString(3, "Python"); ps.executeUpdate();
            ps.setInt(1, 3); ps.setString(2, "Bob"); ps.setString(3, "JAVA"); ps.executeUpdate();
            ps.setInt(1, 4); ps.setString(2, "Emma"); ps.setString(3, "C++"); ps.executeUpdate();
            ps.setInt(1, 5); ps.setString(2, "Mike"); ps.setString(3, "JAVA"); ps.executeUpdate();

            ps = con.prepareStatement("SELECT * FROM Teacher WHERE Subject = ?");
            ps.setString(1, "JAVA");
            ResultSet rs = ps.executeQuery();
            while (rs.next()) {
                System.out.println(rs.getInt("TNo") + " " + rs.getString("TName") + " " + rs.getString("Subject"));
            }
            con.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
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Slip 18
===========
Question 1: Write a Java program using Multithreading to display all the vowels from a given String...
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import java.util.Scanner;

public class VowelThread extends Thread {
    private String input;

    public VowelThread(String input) {
        this.input = input;
    }

    public void run() {
        for (char ch : input.toLowerCase().toCharArray()) {
            if ("aeiou".indexOf(ch) != -1) {
                System.out.println(ch);
                try {
                    Thread.sleep(3000); // 3 seconds delay
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter a string: ");
        String str = sc.nextLine();
        VowelThread thread = new VowelThread(str);
        thread.start();
        sc.close();
    }
}
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Question 2: Write a SERVLET program in Java to accept details of student...
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<!-- student.html -->
<html>
<body>
<h2>Enter Student Details</h2>
<form action="StudentServlet" method="post">
    Seat No: <input type="text" name="seatNo"><br>
    Name: <input type="text" name="studName"><br>
    Class: <input type="text" name="className"><br>
    Total Marks: <input type="text" name="totalMarks"><br>
    <input type="submit" value="Submit">
</form>
</body>
</html>

<!-- StudentServlet.java -->
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class StudentServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();

        String seatNo = request.getParameter("seatNo");
        String studName = request.getParameter("studName");
        String className = request.getParameter("className");
        double totalMarks = Double.parseDouble(request.getParameter("totalMarks"));

        double percentage = (totalMarks / 500.0) * 100; // Assuming 500 is max marks
        String grade = (percentage >= 80) ? "A" : (percentage >= 60) ? "B" : (percentage >= 40) ? "C" : "D";

        out.println("<html><body>");
        out.println("<h2>Student Details</h2>");
        out.println("Seat No: " + seatNo + "<br>");
        out.println("Name: " + studName + "<br>");
        out.println("Class: " + className + "<br>");
        out.println("Total Marks: " + totalMarks + "<br>");
        out.println("Percentage: " + percentage + "%<br>");
        out.println("Grade: " + grade);
        out.println("</body></html>");
    }
}
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Slip 19
===========
Question 1: Write a Java program to accept ‘N’ Integers from a user store them into LinkedList...
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import java.util.LinkedList;
import java.util.Scanner;

public class NegativeIntegers {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        LinkedList<Integer> numbers = new LinkedList<>();

        System.out.print("Enter the number of integers (N): ");
        int n = sc.nextInt();

        System.out.println("Enter " + n + " integers:");
        for (int i = 0; i < n; i++) {
            numbers.add(sc.nextInt());
        }

        System.out.println("Negative integers:");
        for (int num : numbers) {
            if (num < 0) {
                System.out.println(num);
            }
        }
        sc.close();
    }
}
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Question 2: Write a Java program using SERVLET to accept username and password...
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<!-- login.html -->
<html>
<body>
<h2>Login</h2>
<form action="LoginServlet" method="post">
    Username: <input type="text" name="username"><br>
    Password: <input type="password" name="password"><br>
    <input type="submit" value="Login">
</form>
</body>
</html>

<!-- LoginServlet.java -->
import java.io.*;
import java.sql.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class LoginServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();

        String username = request.getParameter("username");
        String password = request.getParameter("password");

        try {
            Class.forName("org.postgresql.Driver");
            Connection con = DriverManager.getConnection("jdbc:postgresql://localhost:5432/testdb", "postgres", "password");
            PreparedStatement ps = con.prepareStatement("SELECT * FROM users WHERE username = ? AND password = ?");
            ps.setString(1, username);
            ps.setString(2, password);
            ResultSet rs = ps.executeQuery();

            out.println("<html><body>");
            if (rs.next()) {
                out.println("<h2>Login Successful!</h2>");
            } else {
                out.println("<h2>Error: Invalid username or password</h2>");
            }
            out.println("</body></html>");
            con.close();
        } catch (Exception e) {
            out.println("Error: " + e.getMessage());
        }
    }
}
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Slip 22
===========
Question 1: Write a Menu Driven program in Java for the following...
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import java.sql.*;
import java.util.Scanner;

public class EmployeeMenu {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        try {
            Class.forName("org.postgresql.Driver");
            Connection con = DriverManager.getConnection("jdbc:postgresql://localhost:5432/testdb", "postgres", "password");
            Statement stmt = con.createStatement();
            stmt.executeUpdate("CREATE TABLE IF NOT EXISTS Employee (ENo INT, EName VARCHAR(50), Salary DOUBLE)");

            while (true) {
                System.out.println("\n1. Insert\n2. Update\n3. Display\n4. Exit");
                System.out.print("Enter choice: ");
                int choice = sc.nextInt();

                switch (choice) {
                    case 1: // Insert
                        System.out.print("Enter ENo: ");
                        int eno = sc.nextInt();
                        System.out.print("Enter EName: ");
                        String ename = sc.next();
                        System.out.print("Enter Salary: ");
                        double salary = sc.nextDouble();
                        PreparedStatement ps = con.prepareStatement("INSERT INTO Employee VALUES (?, ?, ?)");
                        ps.setInt(1, eno);
                        ps.setString(2, ename);
                        ps.setDouble(3, salary);
                        ps.executeUpdate();
                        System.out.println("Record inserted.");
                        break;

                    case 2: // Update
                        System.out.print("Enter ENo to update: ");
                        eno = sc.nextInt();
                        System.out.print("Enter new Salary: ");
                        salary = sc.nextDouble();
                        ps = con.prepareStatement("UPDATE Employee SET Salary = ? WHERE ENo = ?");
                        ps.setDouble(1, salary);
                        ps.setInt(2, eno);
                        ps.executeUpdate();
                        System.out.println("Record updated.");
                        break;

                    case 3: // Display
                        ResultSet rs = stmt.executeQuery("SELECT * FROM Employee");
                        while (rs.next()) {
                            System.out.println(rs.getInt("ENo") + " " + rs.getString("EName") + " " + rs.getDouble("Salary"));
                        }
                        break;

                    case 4: // Exit
                        con.close();
                        sc.close();
                        System.exit(0);

                    default:
                        System.out.println("Invalid choice!");
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
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Question 2: Write a JSP program which accepts UserName in a TextField and greets the user...
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<%@ page import="java.util.Calendar" %>
<html>
<body>
<h2>Greeting</h2>
<form method="post">
    Enter Username: <input type="text" name="username">
    <input type="submit" value="Greet">
</form>
<%
    String username = request.getParameter("username");
    if (username != null) {
        Calendar cal = Calendar.getInstance();
        int hour = cal.get(Calendar.HOUR_OF_DAY);
        String greeting;
        if (hour < 12) {
            greeting = "Good Morning";
        } else if (hour < 17) {
            greeting = "Good Afternoon";
        } else {
            greeting = "Good Evening";
        }
%>
<p><%= greeting %>, <%= username %>!</p>
<% } %>
</body>
</html>
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Slip 23
===========
Question 1: Write a Java program using Multithreading to accept a String from a user...
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import java.util.Scanner;

public class VowelDisplayThread extends Thread {
    private String input;

    public VowelDisplayThread(String input) {
        this.input = input;
    }

    public void run() {
        for (char ch : input.toLowerCase().toCharArray()) {
            if ("aeiou".indexOf(ch) != -1) {
                System.out.println(ch);
                try {
                    Thread.sleep(3000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter a string: ");
        String str = sc.nextLine();
        VowelDisplayThread thread = new VowelDisplayThread(str);
        thread.start();
        sc.close();
    }
}
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Question 2: Write a Java program to accept 'N' student names through command line...
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import java.util.ArrayList;
import java.util.Iterator;
import java.util.ListIterator;

public class StudentNames {
    public static void main(String[] args) {
        if (args.length == 0) {
            System.out.println("Please provide student names as command-line arguments.");
            return;
        }

        ArrayList<String> students = new ArrayList<>();
        for (String name : args) {
            students.add(name);
        }

        System.out.println("Using Iterator:");
        Iterator<String> iterator = students.iterator();
        while (iterator.hasNext()) {
            System.out.println(iterator.next());
        }

        System.out.println("\nUsing ListIterator (reverse order):");
        ListIterator<String> listIterator = students.listIterator(students.size());
        while (listIterator.hasPrevious()) {
            System.out.println(listIterator.previous());
        }
    }
}
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Slip 25
===========
Question 1: Write a Java program using multithreading to print even numbers from 1 to 20 with a 1-second delay.
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public class EvenNumberThread extends Thread {
    public void run() {
        for (int i = 1; i <= 20; i++) {
            if (i % 2 == 0) {
                System.out.println(i);
                try {
                    Thread.sleep(1000); // 1-second delay
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    public static void main(String[] args) {
        EvenNumberThread thread = new EvenNumberThread();
        thread.start();
    }
}
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Question 2: Write a JSP program to display the current date and time.
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<%@ page import="java.util.Date" %>
<html>
<body>
<h2>Current Date and Time</h2>
<p>Current Date and Time: <%= new Date() %></p>
</body>
</html>
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Slip 26
===========
Question 1: Write a Java program to delete the details of given employee...
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import java.sql.*;
import java.util.Scanner;

public class DeleteEmployee {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter Employee ID to delete: ");
        int eno = sc.nextInt();

        try {
            Class.forName("org.postgresql.Driver");
            Connection con = DriverManager.getConnection("jdbc:postgresql://localhost:5432/testdb", "postgres", "password");
            PreparedStatement ps = con.prepareStatement("DELETE FROM Employee WHERE ENo = ?");
            ps.setInt(1, eno);
            int rows = ps.executeUpdate();
            if (rows > 0) {
                System.out.println("Employee with ENo " + eno + " deleted successfully.");
            } else {
                System.out.println("No employee found with ENo " + eno);
            }
            con.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
        sc.close();
    }
}
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Question 2: Write a JSP program to calculate sum of first and last digit of a given number...
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<html>
<body>
<h2>Sum of First and Last Digit</h2>
<form method="post">
    Enter Number: <input type="text" name="num">
    <input type="submit" value="Calculate">
</form>
<%
    String numStr = request.getParameter("num");
    if (numStr != null) {
        int num = Integer.parseInt(numStr);
        int firstDigit = num;
        while (firstDigit >= 10) {
            firstDigit /= 10;
        }
        int lastDigit = num % 10;
        int sum = firstDigit + lastDigit;
%>
<p style="color:red; font-size:18px;">Sum of first and last digit: <%= sum %></p>
<% } %>
</body>
</html>
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Slip 28
===========
Question 1: Write a JSP script to accept a String from a user and display it in reverse order.
--------------------------------------------------------------------------------
<html>
<body>
<h2>Reverse String</h2>
<form method="post">
    Enter String: <input type="text" name="str">
    <input type="submit" value="Reverse">
</form>
<%
    String str = request.getParameter("str");
    if (str != null) {
        StringBuilder reversed = new StringBuilder(str).reverse();
%>
<p>Reversed String: <%= reversed %></p>
<% } %>
</body>
</html>
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Question 2: Write a Java program to display name of currently executing Thread in multithreading.
--------------------------------------------------------------------------------
public class CurrentThreadDemo extends Thread {
    public CurrentThreadDemo(String name) {
        super(name);
    }

    public void run() {
        System.out.println("Currently executing thread: " + Thread.currentThread().getName());
    }

    public static void main(String[] args) {
        CurrentThreadDemo t1 = new CurrentThreadDemo("Thread-1");
        CurrentThreadDemo t2 = new CurrentThreadDemo("Thread-2");

        t1.start();
        t2.start();
    }
}
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Slip 29
===========
Question 1: Write a Java program to display information about all columns in the DONAR table...
--------------------------------------------------------------------------------
import java.sql.*;

public class DonarMetaData2 {
    public static void main(String[] args) {
        try {
            Class.forName("org.postgresql.Driver");
            Connection con = DriverManager.getConnection("jdbc:postgresql://localhost:5432/testdb", "postgres", "password");
            PreparedStatement ps = con.prepareStatement("SELECT * FROM DONAR");
            ResultSet rs = ps.executeQuery();
            ResultSetMetaData rsmd = rs.getMetaData();

            int columnCount = rsmd.getColumnCount();
            System.out.println("Total Columns: " + columnCount);
            for (int i = 1; i <= columnCount; i++) {
                System.out.println("Column " + i + ":");
                System.out.println("Name: " + rsmd.getColumnName(i));
                System.out.println("Type: " + rsmd.getColumnTypeName(i));
                System.out.println("Size: " + rsmd.getColumnDisplaySize(i));
                System.out.println();
            }
            con.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
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Question 2: Write a Java program to create LinkedList of integer objects and perform the following...
--------------------------------------------------------------------------------
import java.util.LinkedList;

public class LinkedListOperations {
    public static void main(String[] args) {
        LinkedList<Integer> list = new LinkedList<>();

        // Adding some initial elements
        list.add(10);
        list.add(20);
        list.add(30);

        // i. Add element at first position
        list.addFirst(5);
        System.out.println("After adding at first position: " + list);

        // ii. Delete last element
        list.removeLast();
        System.out.println("After deleting last element: " + list);

        // iii. Display the size of the list
        System.out.println("Size of the list: " + list.size());
    }
}
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