DEV Community: Saravanan Lakshmanan

Java Learning Series - Updated Product Management System

Saravanan Lakshmanan — Thu, 10 Sep 2026 18:31:18 +0000

Today, I learnt how to import a file using File class object instead of creating multiple objects.

Products.java

public class Product{

    private int id;
    private String name;
    private String category;
    private int price;

    public Product(int i, String n, String c, int p) {
        this.id = i;
        this.name = n;
        this.category = c;
        this.price = p;
    }

    public int getId() {
        return this.id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return this.name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getCategory() {
        return this.category;
    }

    public void setCategory(String category) {
        this.category = category;
    }

    public int getPrice() {
        return this.price;
    }

    public void setPrice(int price) {
        this.price = price;
    }

    public String toString() {
        return this.getId() + " , " + this.getName() + " , " + this.getCategory() + " , " + this.getPrice();
    }
}

ProductService.java

import java.util.ArrayList;

public class ProductService{

    ArrayList<Product> arr = new ArrayList();

    public void addProduct(Product product) {
        boolean addStatus = arr.add(product);
        if (addStatus) {
            System.out.println("Product is Added");
        } else {
            System.out.println("Product is not Added");
        }
    }

    public void viewProduct() {
        for (Product product : arr) {
            System.out.println(product);
        }
    }

    public void searchProduct(int id) {
        System.out.println();
        boolean found = false;

        for (Product product : arr) {
            if (product.getId() == id) {
                System.out.println(product.getId() + " - " + product.getName() + " - " + product.getCategory() + " - " + product.getPrice());
                found = true;
                break;
            }
        }

        if (found == true) {
            System.out.println("Product is Found");
        } else {
            System.out.println("Product is not Found");
        }
    }

    public void updateProduct(Product newProduct) {
        for (Product existingProduct : arr) {
            if (existingProduct.getId() == newProduct.getId()) {
                existingProduct.setName(newProduct.getName());
                existingProduct.setCategory(newProduct.getCategory());
                existingProduct.setPrice(newProduct.getPrice());
            }
        }
    }

    public void deleteProduct(int id) {
        boolean deleteStatus = false;

        for (Product product : arr) {
            if (product.getId() == id) {
                arr.remove(product);
                deleteStatus = true;
                break;
            }
        }

        if (deleteStatus == true) {
            System.out.println("Product is Deleted");
        } else {
            System.out.println("Product is Not Found");
        }
    }
}

Main.java

import java.io.File;
import java.io.FileReader;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.FileNotFoundException;

public class Main{

    public static void main(String[] args) {

        ProductService service = new ProductService();

        File file = new File("products.csv");
//        System.out.println(file.canRead());

        try{
            FileReader reader = new FileReader(file);
            BufferedReader br = new BufferedReader(reader);
            String line = br.readLine();

            line = br.readLine();
            while(line!=null){
                String[] data = line.split(",");
//                System.out.println(data);
//                System.out.println(line);

                    int id = Integer.parseInt(data[0]);
                    String name = data[1];
                    String category = data[2];
                    int price = Integer.parseInt(data[3]);

                Product product = new Product(id, name, category, price);
                service.addProduct(product);

//                    System.out.println(data[0]);
//                    System.out.println(data[1]);
//                    System.out.println(data[2]);
//                    System.out.println(data[3]);

//                for(int i = 0; i<data.length; i++){
//                    System.out.println(data[i]);
//                }

//                for(String str : data){
//                    System.out.println(str);
//                }
                line = br.readLine();
            }



        }catch(FileNotFoundException file_Obj){
            System.out.println("FileNotFoundException - Error");
        }catch(IOException io_Obj){
            System.out.println("IOException - Error");
        }


//        Product p1 = new Product(101, "Laptop", "Electronics", 50000);
//        Product p2 = new Product(102, "Mobile", "Electronics", 30000);
//        Product p3 = new Product(102, "Chair", "Furniture", 5000);
//        service.addProduct(p2);
//
        service.viewProduct();
//
        service.searchProduct(102);

//        service.updateProduct(p3);

        service.viewProduct();

        service.deleteProduct(101);

        service.viewProduct();
//
    }
}

Output:

Product is Added
Product is Added
Product is Added
101 , Laptop , Electronics , 50000
102 , Mobile , Electronics , 20000
103 , Chair , Furniture , 10000

102 - Mobile - Electronics - 20000
Product is Found
101 , Laptop , Electronics , 50000
102 , Mobile , Electronics , 20000
103 , Chair , Furniture , 10000
Product is Deleted
102 , Mobile , Electronics , 20000
103 , Chair , Furniture , 10000

Java Learning Series - Exploring Java File Class: Listing Files and Folders

Saravanan Lakshmanan — Wed, 09 Sep 2026 18:47:17 +0000

Today, I explored Java File class and created the mini task using it's methods.

import java.io.File;
import java.io.IOException;

public class FileList {

    public static void main(String[] args){
        File file = new File("/home/saravanan/FullStack/front-end/Back-end/Java");
        File[] files = file.listFiles();
            System.out.println();
            System.out.println(files); //tried to print the entire Objects in an Array
            System.out.println();
            System.out.println("List of Files: ");
            System.out.println();

        for(File obj : files){
            boolean fileStatus = obj.isFile();
//          boolean folderStatus = obj.isDirectory();
            if(fileStatus){
                System.out.println("File Name: " + obj.getName());
                System.out.println("Path : " + obj.getPath());
                System.out.println("Absolute Path : " + obj.getAbsolutePath());
                try{
                System.out.println("Canonical Path : " + obj.getCanonicalPath());
                }catch(IOException io){
                    System.out.println("Canonical Path Error");
                }
                System.out.println("File Length: " + obj.length());
                System.out.println();
            }

//            if(folderStatus){
//                System.out.println(obj.getName());
//            }

        }
            System.out.println();
            System.out.println("List of Folders: ");
            System.out.println();

        for(int i = 0; i<files.length; i++){
            boolean folderStatus = files[i].isDirectory();
        if(folderStatus){
            System.out.println("Folder Name: " + files[i].getName());
            System.out.println("Path : " + files[i].getPath());
            System.out.println("Absolute Path : " + files[i].getAbsolutePath());
            try{
                System.out.println("Canonical Path: " + files[i].getCanonicalPath());
                }catch(IOException io){
                    System.out.println("Canonical Path Error");
                }
            System.out.println("Folder Length: " + files[i].length());
            System.out.println();
        }
        }
    }

}

Output:

[Ljava.io.File;@2a139a55

List of Files: 

File Name: Customers.class
Path : /home/saravanan/FullStack/front-end/Back-end/Java/Customers.class
Absolute Path : /home/saravanan/FullStack/front-end/Back-end/Java/Customers.class
Canonical Path : /home/saravanan/FullStack/front-end/Back-end/Java/Customers.class
File Length: 530

File Name: Student.class
Path : /home/saravanan/FullStack/front-end/Back-end/Java/Student.class
Absolute Path : /home/saravanan/FullStack/front-end/Back-end/Java/Student.class
Canonical Path : /home/saravanan/FullStack/front-end/Back-end/Java/Student.class
File Length: 902

File Name: FileList.java
Path : /home/saravanan/FullStack/front-end/Back-end/Java/FileList.java
Absolute Path : /home/saravanan/FullStack/front-end/Back-end/Java/FileList.java
Canonical Path : /home/saravanan/FullStack/front-end/Back-end/Java/FileList.java
File Length: 2150

File Name: Student.java
Path : /home/saravanan/FullStack/front-end/Back-end/Java/Student.java
Absolute Path : /home/saravanan/FullStack/front-end/Back-end/Java/Student.java
Canonical Path : /home/saravanan/FullStack/front-end/Back-end/Java/Student.java
File Length: 1094

File Name: SuperMarket.java
Path : /home/saravanan/FullStack/front-end/Back-end/Java/SuperMarket.java
Absolute Path : /home/saravanan/FullStack/front-end/Back-end/Java/SuperMarket.java
Canonical Path : /home/saravanan/FullStack/front-end/Back-end/Java/SuperMarket.java
File Length: 1210

File Name: Customers.java
Path : /home/saravanan/FullStack/front-end/Back-end/Java/Customers.java
Absolute Path : /home/saravanan/FullStack/front-end/Back-end/Java/Customers.java
Canonical Path : /home/saravanan/FullStack/front-end/Back-end/Java/Customers.java
File Length: 377

File Name: Grt.java
Path : /home/saravanan/FullStack/front-end/Back-end/Java/Grt.java
Absolute Path : /home/saravanan/FullStack/front-end/Back-end/Java/Grt.java
Canonical Path : /home/saravanan/FullStack/front-end/Back-end/Java/Grt.java
File Length: 504

File Name: StudentService.java
Path : /home/saravanan/FullStack/front-end/Back-end/Java/StudentService.java
Absolute Path : /home/saravanan/FullStack/front-end/Back-end/Java/StudentService.java
Canonical Path : /home/saravanan/FullStack/front-end/Back-end/Java/StudentService.java
File Length: 1497


List of Folders: 

Folder Name: Pro1
Path : /home/saravanan/FullStack/front-end/Back-end/Java/Pro1
Absolute Path : /home/saravanan/FullStack/front-end/Back-end/Java/Pro1
Canonical Path: /home/saravanan/FullStack/front-end/Back-end/Java/Pro1
Folder Length: 4096

Folder Name: Pro2
Path : /home/saravanan/FullStack/front-end/Back-end/Java/Pro2
Absolute Path : /home/saravanan/FullStack/front-end/Back-end/Java/Pro2
Canonical Path: /home/saravanan/FullStack/front-end/Back-end/Java/Pro2
Folder Length: 4096

Folder Name: Inheritance-Method_Overriding
Path : /home/saravanan/FullStack/front-end/Back-end/Java/Inheritance-Method_Overriding
Absolute Path : /home/saravanan/FullStack/front-end/Back-end/Java/Inheritance-Method_Overriding
Canonical Path: /home/saravanan/FullStack/front-end/Back-end/Java/Inheritance-Method_Overriding
Folder Length: 4096

Folder Name: StudentManagementSystem
Path : /home/saravanan/FullStack/front-end/Back-end/Java/StudentManagementSystem
Absolute Path : /home/saravanan/FullStack/front-end/Back-end/Java/StudentManagementSystem
Canonical Path: /home/saravanan/FullStack/front-end/Back-end/Java/StudentManagementSystem
Folder Length: 4096

Folder Name: ProductManagementSystem
Path : /home/saravanan/FullStack/front-end/Back-end/Java/ProductManagementSystem
Absolute Path : /home/saravanan/FullStack/front-end/Back-end/Java/ProductManagementSystem
Canonical Path: /home/saravanan/FullStack/front-end/Back-end/Java/ProductManagementSystem
Folder Length: 4096

Java Learning Series - Product Management System

Saravanan Lakshmanan — Tue, 08 Sep 2026 18:40:43 +0000

Today, I created Product Management System in Java.

Product.java

public class Product{

    private int id;
    private String name;
    private String category;
    private int price;

    public Product(int i, String n, String c, int p) {
        this.id = i;
        this.name = n;
        this.category = c;
        this.price = p;
    }

    public int getId() {
        return this.id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return this.name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getCategory() {
        return this.category;
    }

    public void setCategory(String category) {
        this.category = category;
    }

    public int getPrice() {
        return this.price;
    }

    public void setPrice(int price) {
        this.price = price;
    }

    public String toString() {
        return this.getId() + " , " + this.getName() + " , " + this.getCategory() + " , " + this.getPrice();
    }
}

ProductService.java

import java.util.ArrayList;

public class ProductService{

    ArrayList<Product> arr = new ArrayList();

    public void addProduct(Product product) {
        boolean addStatus = arr.add(product);
        if (addStatus) {
            System.out.println("Product is Added");
        } else {
            System.out.println("Product is not Added");
        }
    }

    public void viewProduct() {
        for (Product product : arr) {
            System.out.println(product);
        }
    }

    public void searchProduct(int id) {
        System.out.println();
        boolean found = false;

        for (Product product : arr) {
            if (product.getId() == id) {
                System.out.println(product.getId() + " - " + product.getName() + " - " + product.getCategory() + " - " + product.getPrice());
                found = true;
                break;
            }
        }

        if (found == true) {
            System.out.println("Product is Found");
        } else {
            System.out.println("Product is not Found");
        }
    }

    public void updateProduct(Product newProduct) {
        for (Product existingProduct : arr) {
            if (existingProduct.getId() == newProduct.getId()) {
                existingProduct.setName(newProduct.getName());
                existingProduct.setCategory(newProduct.getCategory());
                existingProduct.setPrice(newProduct.getPrice());
            }
        }
    }

    public void deleteProduct(int id) {
        boolean deleteStatus = false;

        for (Product product : arr) {
            if (product.getId() == id) {
                arr.remove(product);
                deleteStatus = true;
                break;
            }
        }

        if (deleteStatus == true) {
            System.out.println("Product is Deleted");
        } else {
            System.out.println("Product is Not Found");
        }
    }
}

Main.java

public class Main{

    public static void main(String[] args) {

        Product p1 = new Product(101, "Laptop", "Electronics", 50000);
        Product p2 = new Product(102, "Mobile", "Electronics", 30000);
        Product p3 = new Product(102, "Chair", "Furniture", 5000);

        ProductService service = new ProductService();

        service.addProduct(p1);
        service.addProduct(p2);

        service.viewProduct();

        service.searchProduct(102);

        service.updateProduct(p3);

        service.viewProduct();

        service.deleteProduct(101);

        service.viewProduct();

    }
}

Output:

Product is Added
Product is Added
101 , Laptop , Electronics , 50000
102 , Mobile , Electronics , 30000

102 - Mobile - Electronics - 30000
Product is Found
101 , Laptop , Electronics , 50000
102 , Chair , Furniture , 5000
Product is Deleted
102 , Chair , Furniture , 5000

Java Learning Series - Inheritance & Method-Overriding

Saravanan Lakshmanan — Mon, 07 Sep 2026 15:47:00 +0000

Today, I learnt Inheritance & Method-Overriding and made a mini-task.

Inheritance - Child class can use Parent class method using keyword extends, instead of creating it again in Child class.

Method-Overriding - Instead of using the same implementation/logic of Parent class method, Child class can override it's own implementation but with same method name, same number of arguments, same type of arguments and same return type.

Parent.java

public class Parent{

    public void parent_method(){
        System.out.println("I'm Parent Method'");
    }

}

Child.java

public class Child extends Parent{

    public static void main(String[] args){

        Child c = new Child();

        c.parent_method(); //checked for Inheritance concept
        c.parent_method(); //called for Method-Overriding

    }

    @Override
    public void parent_method(){
        System.out.println("I'm new Child method now'");
    }


}

Main.java

public class Main{

    public static void main(String[] args){
        Child c = new Child();
        Parent p = new Parent();

        c.parent_method();
        p.parent_method();
    }

}

Output:

I'm new Child method now'
I'm Parent Method'

Python Learning Series - Python Pattern Task

Saravanan Lakshmanan — Fri, 04 Sep 2026 05:54:56 +0000

Task 1:

for row in range(1,6):
    for col in range(1,row+1):
        print(0 if (row+col) % 2 == 0 else 1, end = '\t')
    print()

Output:

0   
1   0   
0   1   0   
1   0   1   0   
0   1   0   1   0

Task 2:


for row in range(1,6):
    for col in range(1,row+1):
        print(1 if (col % 2) == 0 else 0, end = '\t')
    print()

Output:

0   
0   1   
0   1   0   
0   1   0   1   
0   1   0   1   0

Task 3:

for row in range(1,6):
    for col in range(1,row+1):
        print(1 if (row % 2) == 0 else 0, end = '\t')
    print()

Output:

0   
1   1   
0   0   0   
1   1   1   1   
0   0   0   0   0

Java Learning Series - Student Management System

Saravanan Lakshmanan — Wed, 02 Sep 2026 20:05:25 +0000

Today, I practiced and built a simple Student Management System using Java with separate classes for better code organization.

Add Student
View Students
Search Student
Delete Student
Modify Student

Practicing Java OOP, Classes, Objects, ArrayList, and Methods.

Student.java

public class Student{

    private int id;
    private String name;
    private String course;
    private int mark;

    public Student(int id, String name, String course, int mark){
        this.id = id;
        this.name = name;
        this.course = course;
        this.mark = mark;
    }

    public int getId(){
        return this.id;
    }

    public void setId(int id){
        this.id = id;
}

    public String getName(){
        return this.name;
}

    public void setName(String name){
        this.name = name;
}

    public String getCourse(){
        return this.course;
}

    public void setCourse(String course){
        this.course = course;
}

    public int getMark(){
        return this.mark;
}

    public void setMark(int mark){
        this.mark = mark;
}

}

StudentService.java

import java.util.ArrayList;

public class StudentService{

//add
//view
//delete
//search
//modify


    ArrayList<Student> arr = new ArrayList();

public void addStudent(Student student){
    arr.add(student);
}

public void viewStudent(){
        System.out.println();
        System.out.println("**********The Student List************************");
    for(Student student : arr){
        System.out.println("Student Id: " + student.getId());
        System.out.println("Student Name: " + student.getName());
        System.out.println("Student Course: " + student.getCourse());
        System.out.println("Student Mark: " + student.getMark());
        System.out.println();
}
        System.out.println("****************************************************");
        System.out.println();
}

public void updateStudent(int id, String name, String course, int mark){
    for(Student student : arr){
        if(student.getId() == id){
             System.out.println("**********Student Updated**************************");
             student.setName(name);
             student.setCourse(course);
             student.setMark(mark);
             System.out.println("****************************************************");
             System.out.println();
             return;

    }
    }
   System.out.println("Student Not Found");
}

public void searchStudent(int id){
        System.out.println();
        System.out.println("**********Search List************************");
    for(Student student : arr){
        if(student.getId() == id){
             System.out.println("Student Found");
             System.out.println("Student ID: " + student.getId());
             System.out.println("Student Name: " + student.getName());
             System.out.println("Student Course: " + student.getCourse());
             System.out.println("Student Mark: " + student.getMark());
             System.out.println();
             return;
}
} 
   System.out.println("Student Not Found");
}

public void deleteStudent(int id){
        System.out.println();
        System.out.println("*********************************************");
    for(Student student : arr){
        if(student.getId() == id){
            arr.remove(student);
            System.out.println("Student Deleted");
            return;
    }
}
   System.out.println("Student Not Found");
}

}

Main.java

public class Main{

    public static void main(String[] args){

        Student s1 = new Student(101,"Saravanan", "Java", 100);  
        Student s2 = new Student(102,"Saran", "JS", 99);        
        Student s3 = new Student(103,"Dhana", "Python", 89);

        StudentService service = new StudentService();

        service.addStudent(s1);
        service.addStudent(s2);
        service.addStudent(s3);

        service.viewStudent();


        service.updateStudent(102, "Ravi", "C#", 77);
        service.viewStudent();

        service.searchStudent(103);

        service.deleteStudent(101);
        service.viewStudent();
    }

}

Output:

**********The Student List************************
Student Id: 101
Student Name: Saravanan
Student Course: Java
Student Mark: 100

Student Id: 102
Student Name: Saran
Student Course: JS
Student Mark: 99

Student Id: 103
Student Name: Dhana
Student Course: Python
Student Mark: 89

****************************************************

**********Student Updated**************************
****************************************************


**********The Student List************************
Student Id: 101
Student Name: Saravanan
Student Course: Java
Student Mark: 100

Student Id: 102
Student Name: Ravi
Student Course: C#
Student Mark: 77

Student Id: 103
Student Name: Dhana
Student Course: Python
Student Mark: 89

****************************************************


**********Search List************************
Student Found
Student ID: 103
Student Name: Dhana
Student Course: Python
Student Mark: 89


*********************************************
Student Deleted

**********The Student List************************
Student Id: 102
Student Name: Ravi
Student Course: C#
Student Mark: 77

Student Id: 103
Student Name: Dhana
Student Course: Python
Student Mark: 89

****************************************************

Python Learning Series - Pattern programs

Saravanan Lakshmanan — Wed, 02 Sep 2026 10:39:34 +0000

Task 1

no = 0
for row in range(6,1,-1):
    for col in range(1,row):  
        no+=1 
        print(no, end = ' ')
    print()

Output:

Task 2

for row in range(6,1,-1):
    for col in range(1,row):
        print(chr(64+col), end = '  ')
    print()

Output:

A B C D E
A B C D
A B C
A B
A

Java Learning Series - Creating POJO class

Saravanan Lakshmanan — Mon, 31 Aug 2026 14:29:41 +0000

Today, I've created POJO (Plain Old Java Object) class for Student Management System and practiced using constructor, getter, setter and encapsulation.

public class Student{
        //creating private non-static global variable
        private int id;
        private String name;
        private String course;
        private int mark;

    //creating constructors with 4 parameters
    public Students(int id, String name, String course, int mark){
        this.id = id;
        this.name = name;
        this.course = course;
        this.mark = mark;
}

    public static void main(String[] args){
           Student s1 = new Student(101,"Saravanan", "BCA", 500);
            s1.getId();

}
    //creating getter & setter methods for id
    public int getId(){
        return this.id;
}
    public void setId(int id){
        this.id = id;
}

    //creating getter & setter methods for name
    public String getName(){
        return this.name;
}
    public void setName(String name){
        this.name = name;
}

    //creating getter & setter methods for course
    public String getCourse(){
        return this.course;
}
    public void setCourse(String course){
        this.course = course;
}

    //creating getter & setter methods for mark
    public int getMark(){
        return this.mark;
}
    public void setMark(int mark){
        this.mark = mark;
}


}

Java Learning Series | Constructors, Methods & Method Overloading

Saravanan Lakshmanan — Thu, 27 Aug 2026 20:35:48 +0000

Concepts Practiced

Class & Objects
Instance Variables
Static Variable
Constructors
Constructor Overloading
this Keyword
Methods
Method Parameters
Method Overloading
Compile-Time Polymorphism
Return Type & return Keyword
Static & Non-Static Methods
Calling Methods using Objects
Separate Methods for GPay, Cash & Card

Code:

public class Supermarket{

    static String supermarketName = "Grace";

    String productName;
    int price;
    int quantity;

    //creating multiple constructors with same class name and different parameter list
    public Supermarket(String productName){
        this.productName = productName;
//        this.quantity = quantity;
}

    public Supermarket(String productName, int price, int quantity){
        this.productName = productName;
        this.price = price;
        this.quantity = quantity;
}

    public Supermarket(String productName, int price)
{
        this.productName = productName;
        this.price = price;
    }

    public static void main(String[] args){
//        System.out.println("Hello World");
        Supermarket product1 = new Supermarket("milk");
        Supermarket product2 = new Supermarket("curd", 20);
        Supermarket product3 = new Supermarket("Biscuit", 10, 3);

        product1.buy();
        product2.buy(30);
        product3.buy(20,"Hi");

        //calling non-static return type function
        int finalPrice = product1.buy(50,5);
        System.out.println("finalPrice: "+finalPrice);

        //calling gpay, cash, card methods
        product3.gpay(200);
        product3.cash(100);
        product3.card(500);

}

    //creating multiple methods with same method name with different parameters list in the same class
    public void buy(){
//        System.out.println("Buy Method");

}

public void buy(int account){
//        System.out.println("Buy Method - account");
//        System.out.println(this.price);
}
public void buy(int i, String payName){
//        System.out.println("Buy Method");
}

//creating method with return type
public int buy(int price, int discount){
    int total = price - discount;
    return total;
}

//creating method for gpay
public void gpay(int amount){
    System.out.println("Payment via Gpay");
    System.out.println("Amount: "+ amount);
}

//creating method for cash
public void cash(int amount){
    System.out.println("Payment via Cash");
    System.out.println("Amount: "+ amount);
}

//creating method for card
public void card(int amount){
    System.out.println("Payment via Card");
    System.out.println("Amount: "+ amount);
}

}

Output:

finalPrice: 45
Payment via Gpay
Amount: 200
Payment via Cash
Amount: 100
Payment via Card
Amount: 500

Python Task

Saravanan Lakshmanan — Thu, 27 Aug 2026 14:34:45 +0000

1. Find Binary to Decimal:

no = 11001
sum = 0
power = 0

while no>0:

    ld = no % 10
    no = no // 10
    decimal = ld * 2**power
    sum = sum + decimal
    power +=1
    # print(ld)

print(sum)
    # print(sum)

Output:

2. Find Decimal to Binary:

decimal = 5
binary = 0
place = 1

power = 0

while decimal > 0:
    rem = decimal % 2
    binary = binary + rem * 10**power
    decimal = decimal // 2
    power += 1

print('binary value:',binary)

Output:

binary value: 101

3. Find Binary to Octal:

no = 11001
binary = no
sum = 0
power = 0

while no>0:

    ld = no % 10
    no = no // 10
    decimal = ld * 2**power
    sum = sum + decimal
    power +=1

print(f'Decimal value of {binary} is {sum}')

decimal = sum
octal = 0
power = 0
while sum>0:
    rem = sum % 8 #1    
    sum = sum // 8   #3
    octal = octal + rem * 10**power
    power += 1
print(f'Octal value of {decimal} is {octal}')

Output:

Decimal value of 11001 is 25
Octal value of 25 is 31

4. GCD/HCF: (TBD)

no1 = 75
no2 = 100

if no1 > no2:
    ln = no1
    sn = no2
else:
    ln = no2
    sn = no1

print('Largest number is',ln)        
print('Smallest number is',sn)     

while True:
    if ln % sn == 0:
        print('GCD is', sn)
        break
    else:
        rem = ln % sn
        ln = sn
        sn = rem

Output:

Largest number is 100
Smallest number is 75
GCD is 25

Java Task

Saravanan Lakshmanan — Wed, 26 Aug 2026 16:28:48 +0000

Create a class called SuperMarket. Assign 2 static variables. Then create 3 Objects. Two objects with 2 arguments. One object with 3 arguments. Then print all the details.

public class SuperMarket{

    //static variables
    static String superMarketName = "Grace Supermarket";
    static int superMarketDoorno = 150;

    //non - static variables
    String name;
    int price;
    int discount;

    //creating constructor with 2 parameters
    public SuperMarket(String name, int price){
    this.name = name; //using this keyword
    this.price = price;
}

    //creating constructor with 3 parameters
    public SuperMarket(String name, int price, int discount){
    this.name = name;
    this.price = price;
    this.discount = discount;
}

    public static void main(String[] args){

    //creating objects with 2 arguments
    SuperMarket m1 = new SuperMarket("Milk", 25);
    SuperMarket m2 = new SuperMarket("Curd", 20);

    //creating objects with 3 arguments
    SuperMarket m3 = new SuperMarket("Dal", 250, 10);

    System.out.println(SuperMarket.superMarketName);
    System.out.println(SuperMarket.superMarketDoorno);

    System.out.println(m1.name);
    System.out.println(m1.price);
    System.out.println(m2.name);
    System.out.println(m2.price);
    System.out.println(m3.name);
    System.out.println(m3.price);
    System.out.println(m3.discount);

}
}

Output:

Grace Supermarket
150
Milk
25
Curd
20
Dal
250
10

Java Fundamentals: Introduction, Features & Execution Flow

Saravanan Lakshmanan — Mon, 24 Aug 2026 12:27:04 +0000

Introduction to Java

Java is a high-level, class-based, object-oriented programming language that was introduced by Sun Microsystems in 1995. It was designed with the goal of making software development simpler, secure, portable, and suitable for different types of platforms.

Java is widely used for developing web applications, backend systems, enterprise applications, desktop applications, cloud applications, and many other types of software. It is especially popular for large-scale backend and enterprise development.

One of the most important characteristics of Java is its platform independence. Java source code is compiled into an intermediate form called bytecode. This bytecode can run on different operating systems through the Java Virtual Machine (JVM). This is commonly associated with the principle "Write Once, Run Anywhere."

How Does Java Work?

The basic execution process of a Java program is:

Java Source Code (.java)
↓
Java Compiler (javac)
↓
Bytecode (.class)
↓
JVM
↓
Machine Code
↓
CPU

The Java compiler converts the source code into bytecode. The JVM then loads and executes this bytecode. Modern JVMs can use Just-In-Time (JIT) compilation to convert frequently executed bytecode into native machine code, which improves runtime performance.

Features of Java

1. Object-Oriented

Java is primarily an object-oriented programming language. It supports concepts such as classes, objects, inheritance, polymorphism, abstraction, and encapsulation.

Object-oriented programming helps developers organize applications into reusable and maintainable components.

2. Platform Independent

Java is designed to be platform independent because Java programs are compiled into bytecode rather than directly into platform-specific machine code.

The same bytecode can run on different operating systems as long as an appropriate JVM is available.

For example:

Windows → JVM → Java Bytecode

Linux → JVM → Same Java Bytecode

macOS → JVM → Same Java Bytecode

This is one of the major reasons Java is associated with "Write Once, Run Anywhere."

3. Simple

Java was designed with a relatively simple and familiar syntax, especially for developers coming from C and C++ backgrounds.

It removes or simplifies several complex features found in C++, such as direct pointer manipulation and manual memory management.

4. Secure

Java provides several mechanisms that contribute to application security.

The JVM verifies bytecode before execution, and Java provides controlled memory access and automatic memory management. These features help reduce certain classes of programming and memory-related errors.

5. Robust

Java is considered robust because it provides features such as strong type checking, exception handling, automatic memory management, and garbage collection.

Garbage collection automatically manages memory by identifying objects that are no longer needed and reclaiming their memory.

6. High Performance

Java provides good runtime performance through modern JVM optimizations and Just-In-Time (JIT) compilation.

The JVM can identify frequently executed sections of code and compile them into native machine code during execution, helping improve performance.

7. Multithreaded

Java supports multithreading, which allows multiple tasks to execute concurrently within a program.

For example, an application may perform background processing while simultaneously responding to user requests.

Multithreading and concurrency are important for building responsive and scalable applications.

8. Portable

Java's bytecode-based execution model makes applications highly portable across different operating systems and hardware environments that provide a compatible JVM.

This reduces the need to create a completely separate version of the application for every operating system.

9. Distributed

Java provides APIs and technologies that can be used to develop applications that communicate across networks and distributed systems.

This makes Java suitable for developing web services, APIs, enterprise applications, and other network-based systems.

10. Rich Standard Library

Java provides a large standard library containing ready-to-use classes and APIs for common programming requirements.

These libraries help developers work with collections, strings, input/output, networking, dates and times, concurrency, and many other tasks without implementing everything from scratch.

11. Large Ecosystem

Java has a large ecosystem of frameworks, libraries, tools, and developer communities.

Technologies such as Spring, Spring Boot, Hibernate, and many other libraries are widely used for building backend and enterprise applications.

Where Is Java Used?

Java is used in many areas of software development, including:

Backend and web application development
Enterprise applications
REST APIs and web services
Cloud applications
Desktop applications
Android and mobile applications
Big data technologies
Distributed systems
Banking and financial applications
Large-scale business applications

Java's combination of portability, object-oriented programming, performance, security, libraries, and a large ecosystem has helped it remain widely used for many years.