The difference between class and object is one of the fundamental concepts that you will encounter when learning Java, or any other object-oriented language. Although these two concepts are the basis of Java, many beginners struggle to understand them at first. Many beginners think that objects and classes are the same, but they actually serve different purposes. Understanding the differences between classes and objects will not only help you understand Java, but also allow you to write more efficient code. Java Classes in Pune
In Java, a class is essentially an outline or template. It is a structure which defines the attributes and behavior of objects, but it does not represent an actual entity. Imagine it as a plan for your design. If you create a Car class, you can include variables like brand, color and speed along with methods such as drive, brake or accelerate. It describes how a car is supposed to look and what it can do, but it doesn’t exist in the program until you create a specific instance. A class, in this sense is more logical than physical. It defines but doesn’t exist on its own.
A object, on the other hand is a concrete example of a class. You can bring a blueprint to life by creating an object. It represents a real world entity. If the Car class was your blueprint, an object would be a red BMW, or a blue Audi. Each object is assigned its own value for each attribute defined by the class. While the red BMW might have a 120 km/h speed, the blue Audi might have 150 km/h speed, both cars share the same behavior and structure defined by the Class. Objects have a physical nature in that they can be accessed by methods in the class and occupy memory.
Consider the following code to illustrate.
class Car { String brand; String color; int speed; void drive() { System.out.println(“The car is driving. “); } void brake() { System.out.println(“The car has stopped. “); } }
Car is used as a design. This does not represent a car yet. You can create objects of this type, like:
Car car2 = New Car(). Car2.brand = Audi. Car2.color = Blue. Car2.speed = 150.
You now have two objects: vehicle1, and vehicle2. Each object is unique, but they share the same methods. This example shows how a single class can be used for multiple objects that have different characteristics.
The main difference between a object and a class is that whereas Objects represent specific entities, classes define the common structure and behaviour. A class can be used to create multiple objects. It is a design that is reused and created only once. A class is a definition and an instance is an object. The class is logical and abstract, while the instance is tangible and in memory.
Imagine a class like the blueprint of an architect for a home. The blueprint is a representation of the layout, design and number of rooms. However, by itself it does not constitute a home. The house is an object when you build the house using that blueprint. Java allows you to create multiple objects from the same Java class, just as multiple houses may be built using the same blueprint.
This difference is important for several reasons. This allows developers to reuse their code, as one class can create many objects. This also allows for encapsulation as each object is responsible for its own data and state. It is important to note that it reflects the real-world in programming where concepts are represented by classes and actual objects are the instances of these concepts. It would be impossible to fully utilize Java’s object-oriented principles without this understanding.
The difference between Java class and object can be summarized in the following way: A class is a blueprint that defines behaviors and properties, while an object, which contains actual values, is an instance. Classes define and objects exist. Java programmers who master this distinction can create more organized, efficient, and reusable code. This knowledge is the foundation for more advanced OOP concepts such as inheritance and polymorphism.
