Difference between the Constructors and Methods

In Java, constructors and methods are important components of a class that help in initializing objects and performing specific operations. A constructor is used to initialize an object when it is created, while a method defines the behavior and functionality of an object.

• Both constructors and methods improve code reusability and program organization.
• Java supports constructor and method overloading for multiple implementations.

Constructor

A constructor in Java is a special method used to initialize objects of a class. It is automatically called when an object is created and assigns initial values to object variables. Constructors help in setting up the initial state of an object.

• Constructor has the same name as the class and does not have a return type.
• It is automatically executed when an object is create

Syntax

class ClassName {
ClassName() {
// initialization code
}
}

import java.io.*;

class Geek {
    int num;
    String name;

    // This would be invoked while an object
    // of that class created.
    Geek()
    {
        System.out.println("Constructor called");
    }
}

class GFG {
    public static void main(String[] args)
    {
        // this would invoke default constructor.
        Geek geek1 = new Geek();

        // Default constructor provides the default
        // values to the object like 0, null
        System.out.println(geek1.name);
        System.out.println(geek1.num);
    }
}

Constructor called
null
0

Method

A method in Java is a block of code that performs a specific task or operation. Methods define the behavior of objects and help in improving code reusability. They execute only when they are called by the program.

• Methods contain a return type, method name, and parameters.
• They help in code reusability and modular programming.

Syntax

class ClassName {
returnType methodName(parameters) {
// method body
}
}

import java.io.*;

class Addition {

    int sum = 0;

    public int addTwoInt(int a, int b)
    {

        // Adding two integer value.
        sum = a + b;

        // Returning summation of two values.
        return sum;
    }
}

class GFG {
    public static void main(String[] args)
    {

        // Creating an instance of Addition class
        Addition add = new Addition();

        // Calling addTwoInt() method
        // to add two integer
        // using instance created
        // in above step.
        int s = add.addTwoInt(1, 2);

        System.out.println("Sum of two "
                           + "integer values: "
                           + s);
    }
}

Sum of two integer values: 3

Constructors Vs Methods