Java Static Variables and Functions

In Java, static variables belong to the class rather than any individual object. They are shared across all instances.
Static functions (or methods) can be called without creating an instance of the class and usually operate on static variables.

Advantages of static members:

Memory efficient — only one copy shared by all objects.
Useful for constants or shared data.
Utility/helper functions can be static.

Example 1: Static Variable in Employee Class

class Employee {
    String name;
    int age;
    static int employeeCount = 0;  // static variable

    Employee(String name, int age) {
        this.name = name;
        this.age = age;
        employeeCount++;  // increment static count
    }
}

public class Test {
    public static void main(String[] args) {
        Employee e1 = new Employee("Alice", 30);
        Employee e2 = new Employee("Bob", 25);
        System.out.println("Total employees: " + Employee.employeeCount);
    }
}

Output:

Total employees: 2

Static variable employeeCount keeps track of how many Employee objects were created, shared by all instances.

Example 2: Static Function in Employee Class

class Employee {
    String name;
    int age;
    static int employeeCount = 0;

    Employee(String name, int age) {
        this.name = name;
        this.age = age;
        employeeCount++;
    }

    static void displayCount() {  // static method
        System.out.println("Employee count: " + employeeCount);
    }
}

public class Test {
    public static void main(String[] args) {
        Employee e1 = new Employee("Alice", 30);
        Employee e2 = new Employee("Bob", 25);

        Employee.displayCount();  // call static method without object
    }
}

Output:

Employee count: 2

Static method displayCount() prints the static employeeCount variable without needing an object instance.

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