What is an Object in Java?

An object is an instance of a class. When a class is defined, no memory is allocated until you create an object of it.

In simple words: A class is a blueprint, and an object is something built from that blueprint.

How to Create an Object in Java?

ClassName objectName = new ClassName();

• ClassName: The name of the class.
• objectName: The variable that holds the object reference.
• new: Keyword to create a new object.
• ClassName(): Constructor call.

Example 1: Simple Object Creation

class Animal {
    void sound() {
        System.out.println("Animals make sounds");
    }
}

public class Main {
    public static void main(String[] args) {
        Animal myAnimal = new Animal(); // object creation
        myAnimal.sound();               // method call
    }
}

Output:

Animals make sounds

Example 2: Object with Fields

class Car {
    String brand = "Honda";
    int speed = 100;

    void showDetails() {
        System.out.println("Brand: " + brand);
        System.out.println("Speed: " + speed + " km/h");
    }
}

public class Main {
    public static void main(String[] args) {
        Car myCar = new Car(); // create object
        myCar.showDetails();   // access method
    }
}

Output:

Brand: Honda
Speed: 100 km/h

Example 3: Multiple Objects from the Same Class

class Student {
    String name;
    int age;

    void display() {
        System.out.println(name + " is " + age + " years old.");
    }
}

public class Main {
    public static void main(String[] args) {
        Student s1 = new Student(); // 1st object
        s1.name = "Alice";
        s1.age = 20;

        Student s2 = new Student(); // 2nd object
        s2.name = "Bob";
        s2.age = 22;

        s1.display();
        s2.display();
    }
}

Output:

Alice is 20 years old.
Bob is 22 years old.

Object Terminology

Memory Allocation

When an object is created using new, Java allocates memory in heap for that object and returns a reference to it.

Real-Life Example Analogy

Think of a class MobilePhone as a design. You can create multiple phones (objects) like Samsung, iPhone, OnePlus — all using the same design but with different values.