- Java is an object-oriented programming language.
- Everything revolves around class and object.
What is a Class in Java?
- To create a class, use the keyword class.
- A class is a user-defined data type in Java that groups variables and methods together into a single unit.
- A class acts as a blueprint that describes how objects should look and behave.
class Student {
String name;
int age;
void study() {
System.out.println(name + " is studying");
}
}
Here:
name,age → variables
study() → method
Student → class
What is an Object in Java?
- In Java, an object is created from a class.
- An object is a real-world entity created from a class that contains actual data and can use the methods defined in the class.
- An instance of a class means an object created from that class.
Why “Instance” is Important?
- It represents the class in memory.
- Multiple instances can be created from one class.
- Each instance can store different values.
public class Main {
public static void main(String[] args) {
Student s1 = new Student();
s1.name = "Ajay";
s1.age = 21;
s1.study();
}
}