Unit 1.10: Class Methods

Static Methods

Class methods, also known as static methods, are associated with the class itself rather than a specific instance (object) of the class.

Class-Level Behavior

Static methods belong to the class, not to any specific object. A static method can only directly call other static methods within a class.

They are defined using the static keyword. Because static methods belong to the class as a whole, they cannot access instance variables (data tied to a specific object). The main method is the most common example of a static method.

Task: Defining and calling a static method within the same class.

public class Greeter {
    // This is a static method
    public static void sayHello() {
        System.out.println("Hello, World!");
    }

    public static void main(String[] args) {
        // We can call the static method directly because we are inside the same class
        sayHello();
    }
}

Calling Class Methods

Class methods are typically called using the class name, followed by the dot operator (.), the method name, and any required arguments.

The Dot Operator

The . symbol is used to access members of a class or object. For static methods, it tells Java which class contains the code you want to run.

However, if you are calling a static method from within the class where it is defined, providing the class name is optional.

Task: Calling a static method from a different class.

// Assume the Greeter class is defined as above

public class Main {
    public static void main(String[] args) {
        // Calling the sayHello class method from the Greeter class
        // using the format: ClassName.methodName()
        Greeter.sayHello();
    }
}