Classes and objects are fundamental concepts of object-oriented programming in Java. They are used to define and create objects, which are instances of classes, to model real-world entities and their behaviors. A class in Java is a blueprint or a template that defines the structure and behavior of objects. It is a blueprint for creating objects with specific properties (data members) and methods (functions). These created instances can access any methods within a class inside the main method.
A simple class consists of the following:
- Data member
- constructor
- method
- nested class
- interface
public class Dog {
String name;
int age;
public void bark() {
System.out.println("Woof!");
}
public void run() {
System.out.println("The dog is running.");
}
}- Here is a simple class Dog with name and age initialized with this return data type.
- We then create two methods, bark() and run().
On the other hand, an object is an instance of a class. It is created using the new keyword followed by the class name and can be assigned to a variable.
For this example:
Dog doggy = new Dog();- This is how we create objects for a class.
- Now, we can access everything inside the class Dog using the doggy object.
Dog doggy = new Dog();
doggy.name = "Buddy";
doggy.age = 3;
doggy.bark();- We set the name and age properties of the object and then call the bark() method on the object.
Output:
Woof!Conclusion:
Objects allow you to create multiple class instances, each with its properties and behaviors. You can create and use objects of a class in your Java programs to model real-world entities, encapsulate data and behavior, and create reusable code.