Selenium automation testing course with Java- constructors in Java- class 11

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Class 11:
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What is a Constructor in Java?
A constructor in Java is a special method that is automatically called when an object of a class is created. It is used to initialize the object with default or user-defined values.

Syntax of Constructor
=====================
class ClassName {
// Constructor
ClassName() {
// Initialization code
}
}
Note: A constructor must have the same name as the class and cannot have a return type (not even void).

Types of Constructors in Java
==============================
1. Default Constructor- No parameters; Java(Compiler) provides it automatically if no constructor is defined.
2. Parameterized Constructor- Takes parameters to set initial values to instance variables.

Example
========
class Car {
String model;
int year;
Car(String m, int y) {
model = m;
year = y;
}
void display() {
}
}

public class Main {
public static void main(String[] args) {
Car car1 = new Car("Honda City", 2020);
}
}
Uses of Constructors in Java
============================
1. Object Initialization
=======================
Constructors allow setting up initial values of an object’s fields(instance variables).
Without constructors, every field would have to be set manually using setters or other methods.

2. Constructor Overloading
===========================
Java allows multiple constructors with different parameter lists.
This enables flexibility to create objects in different ways.
class Employee {
String name;
int id;

Employee() {} // Default constructor
Employee(String n) { name = n; } // Overloaded
Employee(String n, int i) { name = n; id = i; } // Overloaded
}
3. Improved Code Readability
=============================
Using constructors makes it easier to understand the initial state of objects when reading code.

4. Avoid Code Duplication:-
==========================
You can call one constructor from another using this() to reduce duplication.
class Book {
String title;
int pages;

Book() {
this("Unknown", 100);
}

Book(String t, int p) {
title = t;
pages = p;
}
}
Benefits of Using Constructors
================================
1. Automatic Initialization - Called automatically when an object is created.
2. Code Reusability - Can overload constructors for different use cases.
3. Improved Maintainability - Centralized initialization logic.
4. Encapsulation - Keeps object setup internal and controlled.
5. Default Values - Handling Default constructor can ensure fallback values.
6. Reduced Errors - Prevents objects from remaining in an uninitialized state.

Summary:-
==========
1. A constructor initializes new objects.
2. It has no return type and shares the class name.
3. Constructors improve object creation, readability, and consistency.
4. Java supports constructor overloading for flexibility.