Static and Non-Static Variables in Java

Source: Dev.to

Non-Static (Instance) Variables

In Java, a non‑static variable is declared inside a class but outside any method, without using the static keyword. Each object of the class gets its own separate copy of the variable.

Key Points

• Created when an object is created
• Each object has a different value
• Stored in heap memory
• Accessed using an object reference

Example

class Student {
    int marks;
}

public class Main {
    public static void main(String[] args) {
        Student s1 = new Student();
        Student s2 = new Student();

        s1.marks = 80;
        s2.marks = 90;

        System.out.println(s1.marks); // 80
        System.out.println(s2.marks); // 90
    }
}

Here, marks is a non‑static variable, so each Student object has its own value.

Static Variables

Static variables belong to the class rather than any individual object.

Key Points

• Created once when the class is loaded
• Shared among all objects
• Stored in the method area
• Accessed using the class name (recommended)

Example

public class Employee {
    String name;
    int salary;
    static String company_name = "TCS";

    public static void main(String[] args) {
        Employee mukesh = new Employee();
        mukesh.name = "Mukesh kumar";
        mukesh.salary = 10000;

        Employee hari = new Employee();
        hari.name = "Hari krishnan";
        hari.salary = 20000;
    }
}