Java Model Question Solution 2nd Sem

Q.no 11

public class LogicalOperatorsDemo {
    public static void main(String[] args) {
        boolean a = true, b = false;
        System.out.println("a && b: " + (a && b)); // false
        System.out.println("a || b: " + (a || b)); // true
        System.out.println("!a: " + (!a)); // false
    }
}

public class LogicalOperatorsDemo {

public static void main(String[] args) {

boolean a = true, b = false;

System.out.println("a && b: " + (a && b)); // false

System.out.println("a || b: " + (a || b)); // true

System.out.println("!a: " + (!a)); // false

}

Q.no 12

public class SecondLargest {
    public static void main(String[] args) {
        int[] arr = {12, 35, 1, 10, 34, 1};
        int first = Integer.MIN_VALUE, second = Integer.MIN_VALUE;
        for (int num : arr) {
            if (num > first) { second = first; first = num; } 
            else if (num > second && num != first) { second = num; }
        }
        System.out.println("Second largest: " + (second == Integer.MIN_VALUE ? "Not found" : second));
    }
}

public class SecondLargest {

public static void main(String[] args) {

int[] arr = {12, 35, 1, 10, 34, 1};

int first = Integer.MIN_VALUE, second = Integer.MIN_VALUE;

for (int num : arr) {

if (num > first) { second = first; first = num; }

else if (num > second && num != first) { second = num; }

}

System.out.println("Second largest: " + (second == Integer.MIN_VALUE ? "Not found" : second));

}

Q.no 13

public class MethodOverloadingExample {
    public int add(int a, int b) { return a + b; }
    public int add(int a, int b, int c) { return a + b + c; }
    public double add(double a, double b) { return a + b; }

    public static void main(String[] args) {
        MethodOverloadingExample obj = new MethodOverloadingExample();
        System.out.println(obj.add(5, 10)); // 15
        System.out.println(obj.add(5, 10, 15)); // 30
        System.out.println(obj.add(5.5, 4.5)); // 10.0
    }
}

public class MethodOverloadingExample {

public int add(int a, int b) { return a + b; }

public int add(int a, int b, int c) { return a + b + c; }

public double add(double a, double b) { return a + b; }

public static void main(String[] args) {

MethodOverloadingExample obj = new MethodOverloadingExample();

System.out.println(obj.add(5, 10)); // 15

System.out.println(obj.add(5, 10, 15)); // 30

System.out.println(obj.add(5.5, 4.5)); // 10.0

}

Q.no 14

import java.util.Arrays;
public class GenericSwap {
    public static <T> void swap(T[] array, int i, int j) {
        T temp = array[i]; array[i] = array[j]; array[j] = temp;
    }
    public static void main(String[] args) {
        Integer[] arr = {1, 2, 3, 4, 5};
        swap(arr, 1, 3);
        System.out.println(Arrays.toString(arr)); // [1, 4, 3, 2, 5]
    }
}

import java.util.Arrays;

public class GenericSwap {

public static <T> void swap(T[] array, int i, int j) {

T temp = array[i]; array[i] = array[j]; array[j] = temp;

}

public static void main(String[] args) {

Integer[] arr = {1, 2, 3, 4, 5};

swap(arr, 1, 3);

System.out.println(Arrays.toString(arr)); // [1, 4, 3, 2, 5]

}

Q.no 15

public class FactorialRecursion {
    public static int factorial(int n) { return (n <= 1) ? 1 : n * factorial(n - 1); }

    public static void main(String[] args) {
        System.out.println("Factorial: " + factorial(5)); // Example input: 5 -> Output: 120
    }
}

public class FactorialRecursion {

public static int factorial(int n) { return (n <= 1) ? 1 : n * factorial(n - 1); }

public static void main(String[] args) {

System.out.println("Factorial: " + factorial(5)); // Example input: 5 -> Output: 120

}

Group C

Q.No 17

// Shape.java
interface Shape {
    double area();
    double perimeter();
}

// Circle.java
class Circle implements Shape {
    private double radius;

    public Circle(double radius) {
        this.radius = radius;
    }

    @Override
    public double area() {
        return Math.PI * radius * radius;
    }

    @Override
    public double perimeter() {
        return 2 * Math.PI * radius;
    }
}

// Rectangle.java
class Rectangle implements Shape {
    private double length, breadth;

    public Rectangle(double length, double breadth) {
        this.length = length;
        this.breadth = breadth;
    }

    @Override
    public double area() {
        return length * breadth;
    }

    @Override
    public double perimeter() {
        return 2 * (length + breadth);
    }
}

// Sample.java
public class Sample {
    public static void main(String[] args) {
        Shape circle = new Circle(7);
        Shape rectangle = new Rectangle(5, 10);

        System.out.println("Circle Area: " + circle.area());
        System.out.println("Circle Perimeter: " + circle.perimeter());
        System.out.println("Rectangle Area: " + rectangle.area());
        System.out.println("Rectangle Perimeter: " + rectangle.perimeter());
    }
}

// Shape.java

interface Shape {

double area();

double perimeter();

}

// Circle.java

class Circle implements Shape {

private double radius;

public Circle(double radius) {

this.radius = radius;

}

@Override

public double area() {

return Math.PI * radius * radius;

}

@Override

public double perimeter() {

return 2 * Math.PI * radius;

}

// Rectangle.java

class Rectangle implements Shape {

private double length, breadth;

public Rectangle(double length, double breadth) {

this.length = length;

this.breadth = breadth;

}

@Override

public double area() {

return length * breadth;

}

@Override

public double perimeter() {

return 2 * (length + breadth);

}

// Sample.java

public class Sample {

public static void main(String[] args) {

Shape circle = new Circle(7);

Shape rectangle = new Rectangle(5, 10);

System.out.println("Circle Area: " + circle.area());

System.out.println("Circle Perimeter: " + circle.perimeter());

System.out.println("Rectangle Area: " + rectangle.area());

System.out.println("Rectangle Perimeter: " + rectangle.perimeter());

}

Q.No 18

// Student.java
class Student {
    private String name;
    private double percentage;

    public Student(String name, double percentage) {
        this.name = name;
        this.percentage = percentage;
    }

    public String getName() {
        return name;
    }

    public double getPercentage() {
        return percentage;
    }
}

// StudentDemo.java
public class StudentDemo {
    public static void main(String[] args) {
        Student[] students = {
            new Student("arbind", 85.5),
            new Student("Shyam", 92.0),
            new Student("Hari", 78.5),
            new Student("Rahul", 88.0),
            new Student("Proshesh", 79.5),
            new Student("Kabi", 95.0),
            new Student("Sucess", 89.5),
            new Student("Nutan", 91.0),
            new Student("Jagdish", 94.5),
            new Student("Rajeet", 80.0)
        };

        Student topStudent = students[0];
        for (Student student : students) {
            if (student.getPercentage() > topStudent.getPercentage()) {
                topStudent = student;
            }
        }

        System.out.println("Student with the highest average marks: " + topStudent.getName());
        System.out.println("Percentage: " + topStudent.getPercentage());
    }
}

// Student.java

class Student {

private String name;

private double percentage;

public Student(String name, double percentage) {

this.name = name;

this.percentage = percentage;

}

public String getName() {

return name;

}

public double getPercentage() {

return percentage;

}

// StudentDemo.java

public class StudentDemo {

public static void main(String[] args) {

Student[] students = {

new Student("arbind", 85.5),

new Student("Shyam", 92.0),

new Student("Hari", 78.5),

new Student("Rahul", 88.0),

new Student("Proshesh", 79.5),

new Student("Kabi", 95.0),

new Student("Sucess", 89.5),

new Student("Nutan", 91.0),

new Student("Jagdish", 94.5),

new Student("Rajeet", 80.0)

};

Student topStudent = students[0];

for (Student student : students) {

if (student.getPercentage() > topStudent.getPercentage()) {

topStudent = student;

}

System.out.println("Student with the highest average marks: " + topStudent.getName());

System.out.println("Percentage: " + topStudent.getPercentage());

}

Q.No 19

public class ArrayExample {
    public static void main(String[] args) {
        try {
            int[] numbers = {1, 2, 3};
            System.out.println(numbers[5]); // Invalid index
        } catch (ArrayIndexOutOfBoundsException e) {
            System.out.println("Error: Array index out of bounds!");
        }
    }
}

public class ArrayExample {

public static void main(String[] args) {

try {

int[] numbers = {1, 2, 3};

System.out.println(numbers[5]); // Invalid index

} catch (ArrayIndexOutOfBoundsException e) {

System.out.println("Error: Array index out of bounds!");

}

Q.No 20

import java.io.*;

public class FileReadWrite {
    public static void main(String[] args) {
        // Reading data from "text.txt"
        try (BufferedReader reader = new BufferedReader(new FileReader("text.txt"));
             BufferedWriter writer = new BufferedWriter(new FileWriter("best.txt"))) {

            String line;
            while ((line = reader.readLine()) != null) {
                writer.write(line);
                writer.newLine();
            }

            System.out.println("Data successfully written to best.txt");
        } catch (IOException e) {
            System.out.println("An error occurred: " + e.getMessage());
        }
    }
}

import java.io.*;

public class FileReadWrite {

public static void main(String[] args) {

// Reading data from "text.txt"

try (BufferedReader reader = new BufferedReader(new FileReader("text.txt"));

BufferedWriter writer = new BufferedWriter(new FileWriter("best.txt"))) {

String line;

while ((line = reader.readLine()) != null) {

writer.write(line);

writer.newLine();

}

System.out.println("Data successfully written to best.txt");

} catch (IOException e) {

System.out.println("An error occurred: " + e.getMessage());

}

Group D

Q.No 21

OOP Principles Followed by Java:

Encapsulation: Wrapping data (fields) and methods in a single unit (class).
Abstraction: Hiding implementation details and exposing only essential features.
Inheritance: Mechanism to acquire properties and behaviors of a parent class.
Polymorphism: Ability to perform a single action in different ways (e.g., method overloading and overriding).

Restrictions of Static Methods:

Static methods belong to the class rather than an object.
They cannot access instance variables or instance methods directly.
They cannot use this or super keywords.
They can only call other static methods or use static variables.

Java Program Demonstrating Static Method:

class StaticExample {
    private static int count = 0;

    public static void incrementCount() {
        count++;
    }

    public static int getCount() {
        return count;
    }
}

public class StaticDemo {
    public static void main(String[] args) {
        StaticExample.incrementCount();
        StaticExample.incrementCount();

        System.out.println("Count: " + StaticExample.getCount());
    }
}

class StaticExample {

private static int count = 0;

public static void incrementCount() {

count++;

}

public static int getCount() {

return count;

}

public class StaticDemo {

public static void main(String[] args) {

StaticExample.incrementCount();

System.out.println("Count: " + StaticExample.getCount());

}

Q.no 22

Definition of Inheritance:

Inheritance is a mechanism in object-oriented programming where one class (child/subclass) inherits properties and behaviors (fields and methods) from another class (parent/superclass).

Advantages of Inheritance:

Code Reusability: Allows reuse of existing code.
Extensibility: New features can be added without modifying existing code.
Polymorphism: Enables dynamic method invocation.
Reduced Redundancy: Avoids duplication of code.

Types of Inheritance in Java:

Single Inheritance:

A subclass inherits from a single parent class.

Example:

class Parent {
    void display() {
        System.out.println("This is the parent class.");
    }
}

class Child extends Parent {
    void show() {
        System.out.println("This is the child class.");
    }
}

public class SingleInheritanceDemo {
    public static void main(String[] args) {
        Child child = new Child();
        child.display();
        child.show();
    }
}

class Parent {

void display() {

System.out.println("This is the parent class.");

}

class Child extends Parent {

void show() {

System.out.println("This is the child class.");

}

public class SingleInheritanceDemo {

public static void main(String[] args) {

Child child = new Child();

child.display();

child.show();

}

Multilevel Inheritance:

A class inherits from another class, and that class inherits from another class.

class Grandparent {
    void showGrandparent() {
        System.out.println("This is the grandparent class.");
    }
}

class Parent extends Grandparent {
    void showParent() {
        System.out.println("This is the parent class.");
    }
}

class Child extends Parent {
    void showChild() {
        System.out.println("This is the child class.");
    }
}

public class MultilevelInheritanceDemo {
    public static void main(String[] args) {
        Child child = new Child();
        child.showGrandparent();
        child.showParent();
        child.showChild();
    }
}

class Grandparent {

void showGrandparent() {

System.out.println("This is the grandparent class.");

}

class Parent extends Grandparent {

void showParent() {

System.out.println("This is the parent class.");

}

class Child extends Parent {

void showChild() {

System.out.println("This is the child class.");

}

public class MultilevelInheritanceDemo {

public static void main(String[] args) {

Child child = new Child();

child.showGrandparent();

child.showParent();

child.showChild();

}

Hierarchical Inheritance:

Multiple classes inherit from a single parent class.

class Parent {
    void display() {
        System.out.println("This is the parent class.");
    }
}

class Child1 extends Parent {
    void showChild1() {
        System.out.println("This is child 1.");
    }
}

class Child2 extends Parent {
    void showChild2() {
        System.out.println("This is child 2.");
    }
}

public class HierarchicalInheritanceDemo {
    public static void main(String[] args) {
        Child1 child1 = new Child1();
        child1.display();
        child1.showChild1();

        Child2 child2 = new Child2();
        child2.display();
        child2.showChild2();
    }
}

class Parent {

void display() {

System.out.println("This is the parent class.");

}

class Child1 extends Parent {

void showChild1() {

System.out.println("This is child 1.");

}

class Child2 extends Parent {

void showChild2() {

System.out.println("This is child 2.");

}

public class HierarchicalInheritanceDemo {

public static void main(String[] args) {

Child1 child1 = new Child1();

child1.display();

child1.showChild1();

Child2 child2 = new Child2();

child2.display();

child2.showChild2();

}

OOP Principles Followed by Java:

Restrictions of Static Methods:

Definition of Inheritance:

Advantages of Inheritance:

Types of Inheritance in Java:

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