DEV Community: A K I L A N

Constructor In Java

A K I L A N — Fri, 25 Sep 2026 06:36:15 +0000

Constructor

A constructor in java is a special member that is called when an object is created
It initializes the new object state.
It is used to set default or user-defined values for the object's attributes
A Constructor does not have a return type , not even void
Constructor name should be same as class name

Type of Constructor in java

1.Default Constructor
A default constructor has no parameters.
It used to assign default values to an object
If no constructor is defined
Java provides a default constructor

class Student {

    String name;
    int age;
}

public class Main {

    public static void main(String[] args) {

        Student s = new Student();

        System.out.println(s.name);
        System.out.println(s.age);
    }
}

Output
null 0

2. Parameterized Constructor or Argument Constructor

A constructor that has parameters is known as parameterized constructor
If we want to initialize fields of the class with our own values,then use a parameterized constructo r

public class Object {
   static String name = "Raja";
   static int no = 90;

   String product_name;
   int age;

   public Object(String product_name,int age){
        this.product_name = product_name;
        this.age = age ;
         //System.out.println("I am IRONMAN");
        }


public static void main(String [] args){

    Object product = new Object("Akilan",22);
    Object product1 = new Object("Alagu",21);
    //product.product_name = "Akilan";
   // product1.product_name = "Alagu";
    //product.age = 22;
    //product.age = 21;
    System.out.println(product.product_name);
    System.out.println(product1.product_name);
    System.out.println(product.age);
    System.out.println(product1.age);
    //System.out.println(Object.name);
    //System.out.println(Object.no);
}
}

Output
Akilan Alagu 22 21

Constructor overloading

Same Constructor with different no of arguments or different type of arguments
Static polymorphism
Earily binding
Complie time polymorphism

Object In Java

A K I L A N — Thu, 24 Sep 2026 06:15:24 +0000

Java Objects
An Object is an instance of a class created to access its data and operations
Each object hold its own state
It represents a specific entity created from the class template.
State:Value stored in fields
Behavior:Actions defined through methods
Identity:Distinguishes one object from another
Object Instantiation
Creating an object is known as instantiation .all instances of a class share structure and behavior while storing different state values

public class Object {
   static String name = "Raja";
   static int no = 90;

   String product_name;
   int age;

public static void main(String [] args){

    Object product = new Object();
    Object product1 = new Object();
    product.product_name = "Akilan";
    product1.product_name = "Alagu";
    product.age = 22;
    product.age = 21;
    System.out.println(product.product_name);
    System.out.println(product1.product_name);
    System.out.println(product.age);
    System.out.println(product1.age);
    System.out.println(Object.name);
    System.out.println(Object.no);
}
}

Output:
Akilan
Alagu
21
0
Raja
90

Core Java

A K I L A N — Wed, 23 Sep 2026 06:17:33 +0000

OOPS

Object oriented programming
OOPs organizes the software around object rather than logic and functional
improves code reusablity
OOPS is based on the concept of classes and object
Make code easier to read and understand and mana ge

Class

A class is a blueprint or template used to create objects
It defiens the properties (data) and behaviors(methods) that objects will have
Contains data members and methods.

Python task

A K I L A N — Tue, 22 Sep 2026 10:47:42 +0000

List :

A built in python sequence
Despite its name it is more akin to an array in other language
Group of Individual object into a single entity
we can have duplicates object / elements in list
we can have different datatypes in list
List are mutable

grocery_list = ['soap', 12, True, 'rice', 'veggies',4.5]

print(grocery_list)

output
['soap', 12, True, 'rice', 'veggies', 4.5]

```grocery_list = ['soap', 12, True, 'rice', 'veggies',4.5]

grocery_list[0] = 'shampoo'
print(grocery_list)



**Output**
['shampoo', 12, True, 'rice', 'veggies', 4.5]

List Creation: []
`append() function: adding at the end. `



```python
l=[]
l.append('abcd')
l.append(1234)
l.append(True)
l.append(5.4)
print(l)

output:
['abcd', 1234, True, 5.4]

How to add element at specific position(index) ---> use insert(index,value)

l = ['abcd',1234,True, 5.4]
    #   0   1      2    3
l[-1] = 'pqrs'
print(l)

Output:
['abcd',1234,True, 5.4,'pqrs']

Task

q = [90,87,65,67,89]
h = [96,97,95,69,99]
a = [99,98,100,76,49]

marks = [q,h,a]

Task:
1) Print q, h, a marks in separate lines
2) Calculate Total and Percentage of q, h and a
3) Calculate Average of Tamil (first subject)
4) Calculate highest total among these three

1) Print q, h, a marks in separate lines

for inner_list in marks:
    for elem in inner_list:
        print(elem, end=' ')
    print()

output :
90 87 65 67 89
96 97 95 69 99
99 98 100 76 49

2) Calculate Total and Percentage of q, h and a

for inner_list in marks:
    total =  0
    for elem in inner_list:
        total = total + elem
    print('total is ' ,total)
    print('percentage is ',(total/len(inner_list)))
    print()

Output:
398
79.6

456
91.2

422
84.4
3) Calculate Average of Tamil (first subject)

print('Task - 3')  
total = 0
avg = 1
for inner_list in marks:
    total+=inner_list[0]
avg *= total / 3
print('Total of Tamilsubject :',total)
print('Avg of the Tamilsubject :',avg)

Output:
285
95.0
4) Calculate highest total among these three

```print('Task - 4')
highest = 0
for subject in marks:
total = 0
for mark in subject:
total+=mark
if highest < total :
highest = total
else:
print('Highest Total is ',highest)



output:
Highest Total is  456

JAVA Task

A K I L A N — Tue, 22 Sep 2026 06:19:02 +0000

1) Home.java:10: error: ';' expected
System.out.print("I am AKilan")
^
1 error

public class Home {
public static void main(String[]args){
System.out.print("I am AKilan"_)_
}
}

2)Home.java:10: error: package system does not exist
system.out.print("I am AKilan");
^
1 error

public class Home {
public static void main(String[]args){
_system_.out.print("I am AKilan");
}
}

3)Home.java:10: error: ')' or ',' expected
System.out.print(I am AKilan);
^
Home.java:10: error: ';' expected
System.out.print(I am AKilan);
^
2 errors

public class Home {
public static void main(String[]args){
System.out.print(_I am AKilan_);
}
}

4) Home.java:8: error: class, interface, annotation type, enum, record, method or field expected
public Class Home {
^
Home.java:12: error: class, interface, annotation type, enum, record, method or field expected
}
^
2 errors

public _Class_ Home {
public static void main(String[]args){
System.out.print("I am AKilan");
}
}

5) Home.java:8: error: class home is public, should be declared in a file named home.java
public class home {
^
1 error

public class _home _{
public static void main(String[]args){
System.out.print("I am AKilan");
}
}

6) Home.java:8: error: '{' expected
public class Home
^
1 error

public class Home {
public static void main(String[]args){
System.out.print("I am AKilan");
}

7) Home.java:9: error: invalid method declaration; return type required
public static main(String[]args){
^
1 error

public class Home {
public static  main(String[]args){
System.out.print("I am AKilan");
}
}

8)Home.java:9: error: expected
public static void (String[]args){
^
1 error

public class Home {
public static void (String[]args){
System.out.print("I am AKilan");
}
}

9)missing String Home.java:9: error: illegal start of type
public static void main([]args){
^
Home.java:9: error: ',', ')', or '[' expected
public static void main([]args){
^
2 errors

public class Home {
public static void main([]args){
System.out.print("I am AKilan");
}
}

10) Home.java:9: error: cannot find symbol
public static void main(string[]args){
^
symbol: class string
location: class Home
1 error

public class Home {
public static void main(string[]args){
System.out.print("I am AKilan");
}
}

11) runtime error Error: Main method not found in class Home, please define the main method as:
public static void main(String[] args)
or a JavaFX application class must extend javafx.application.Application

public class Home {
public static void main(String args){
System.out.print("I am AKilan");
}
}

12) Home.java:9: error: expected
public static void main(String[] ){
^
1 error

public class Home {
public static void main(String[] ){
System.out.print("I am AKilan");
}
}

Python In Bulit String methods

A K I L A N — Tue, 22 Sep 2026 05:58:27 +0000

casefold(): Casefold will convert capital alpha to small alpha

txt = "Hello, My Name is AKILAN"
txt2 = "I  AM IRONMAN"
x = txt.casefold()
y= txt2.casefold()
print(x)
print(y)

OUTPUT

hello, my name is akilan
i  am ironman

swapcase(): swapcase will convert uppercase into lowercase and lower to upper

txt = "hello, my name is akilan"
txt2 = "I  AM IRONMAN"
x = txt.swapcase()
y= txt2.swapcase()
print(x)
print(y)

output

HELLO, MY NAME IS AKILAN
i  am ironman

strip()
strip will defaultly remove starting and ending white space if anything not given .
lstrip()
rstrip()
isspace()
isalnum()
isnumeric()
isdigit()

Simple Programs in python

A K I L A N — Wed, 05 Aug 2026 12:42:52 +0000

My trainer gave me 5 question to solve in python the question are look simple when we read line by line sometimes you may understand in different type but there are simple

The questions are

Five students enter the classroom one after another. The first student gets roll number 1, the second gets 2, and so on. Display the assigned roll numbers.

here the answer is

for i in range(1,6):
    print('Student -',i)
    print('Roll no:',i)

from the above

for is the keyword,
i is variable ,
in is use to itrate over the given range() or sequence
sequence given range(),list.

Remaing all three are similar pattens so i will tell the change only

for j in range(2,12,2):
    print("position: ",j)

we can change the starting number and ending number , also step between, we can give step in negative order also

----------------------------x-------------------------------------------x-------

What is Class?

Python is a object orientend language, in python every thing is object with its properties and methods
class is like a blueprint
we can create class name using** class myclass** here **Class **is the keyword
we can delete class using del class_name ** here
**del is the keyword

what is object?

A object is a real instance of a class it contains Data and Methods
data conatins attribute / variables
mean while method contains functions

Function in python

A K I L A N — Wed, 05 Aug 2026 11:46:00 +0000

Function

Function is a set of instructions with a name
A function can return data as a result
Function helps avoiding code repetation

A Function is defined by using def keyword,follwed by a function name and parenteses:

def my_function():
  print("Hello from a function")
my_function();

here def is the keyword,
my_function is the function name,
print() is also function that will give the optput to user,
my_function() will call the function;

Python contains

Type of arguments
type of function
types of variables

Team 4 - TASK

A K I L A N — Wed, 29 Jul 2026 14:03:37 +0000

Enable and diable Button

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <input type="checkbox"  id="agree" >
    <button id="btn" disabled> submit</button>




</body>
<script>

    const input = document.getElementById("agree")
    const button = document.getElementById("btn")

    agree.addEventListener("change",fun)

    function fun() {
         if(input.checked == true)
         {
          button.disabled = false
    } else {
         button.disabled = true
    }
 }


//   agree.addEventListener("change", () =>{
//         button.disabled = !input.checked
//     });



 </script>

</html>

https://akilan46-project-bce2db.gitlab.io/Javascript/DOMTAK.js/team4

Day 3

A K I L A N — Wed, 29 Jul 2026 13:59:12 +0000

Python has a set of keywords that are reserved words that cannot be used as variable names, function names, or any other identifiers:

They Are

['False', 'None', 'True', 'and', 'as', 'assert', 'async', 'await', 'break', 'class', 'continue', 'def', 'del', 'elif', 'else', 'except', 'finally', 'for', 'from', 'global', 'if', 'import', 'in', 'is', 'lambda', 'nonlocal', 'not', 'or', 'pass', 'raise', 'return', 'try', 'while', 'with', 'yield']

Variables can store data of different types, and different types can do different things.

Text Type: str
Numeric Types: int, float, complex
Sequence Types: list, tuple, range
Mapping Type: dict
Set Types: set, frozenset
Boolean Type: bool
Binary Types: bytes, bytearray, memoryview
None Type: NoneType

Domtasks

A K I L A N — Wed, 29 Jul 2026 06:34:22 +0000

LIVE counter

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <p id="dom"></p>
    <button  onclick="add()">+</button>
    <button  onclick="sub()">-</button>
    <button  onclick="start()">Reset</button>
</body>

<script>
    let i = 0;
    //  a = document.getElementById("dom")
    let task = document.getElementById("dom").textContent=i;

    function add(){
        // task++;
        // task.innertext = task++;
        // console.log(task)
        // i++;
        document.getElementById("dom").textContent=++i;

    }
    function sub(){
        // task.innertext = task--;
        // console.log(task)
        // i -=1;
        document.getElementById("dom").textContent=--i;
    }
    function start(){
        // task.innertext = 0 ;
        i = 0;
        document.getElementById("dom").innerText=i;

    }




</script>
</html>

akilan46-project-bce2db.gitlab.io

PYTHON DAY 2

A K I L A N — Tue, 28 Jul 2026 13:20:07 +0000

one of the python feature is python is simple

Difference between python2 and python3

ocusing on the following libraries and modules.

Division operator - in p2 automatically remove decimals,(p3 keeps the decimal)

print function - in p2 for print statement no bracket needed ,(p3 brackets are needed)

Unicode - in p2 string are ASCII by default,& uncicode must be defined seperated (in p3 string are unicode by defualt)

xrange - xrange is used in p2 to find number between (in p3 that hs been removed the use range pro that if we use xrange that shows error)

-Error Handling - p2 uses a comma to bind the exception( in p3 uses as keyword )

- future module - future module allows Python 2 code to adopt Python 3 features early, making migration easier.

2.What is python IDLE ?

idle(integrated development and learning Environment) is the default .lightweight (iDE) bundled directly with the Standrad python installtion