Understanding Java Method Overloading with Examples

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Question :

Introduce Java Method Overloading and give examples

Réponse :

Java Method Overloading

Method overloading in Java is a feature that allows a class to have more than one method with the same name, but with different parameter lists. This means that you can define multiple methods with the same name as long as they have different types, numbers, or order of parameters. Method overloading is a way to achieve polymorphism in Java.

Key Points:

  • Same Method Name: All overloaded methods must have the same name.
  • Different Parameters: They must differ in the type, number, or order of parameters.
  • Return Type: The return type can be different, but it alone cannot be used to distinguish overloaded methods.
  • Compile-time Polymorphism: Method overloading is resolved at compile time.

Examples of Method Overloading

Here are some examples to illustrate method overloading in Java:

Example 1: Basic Method Overloading

class MathOperations {
    
    // Method to add two integers
    int add(int a, int b) {
        return a + b;
    }
    
    // Method to add three integers
    int add(int a, int b, int c) {
        return a + b + c;
    }
    
    // Method to add two double values
    double add(double a, double b) {
        return a + b;
    }
}

public class Main {
    public static void main(String[] args) {
        MathOperations math = new MathOperations();
        
        System.out.println("Sum of 2 and 3: " + math.add(2, 3)); // Calls the first method
        System.out.println("Sum of 2, 3 and 4: " + math.add(2, 3, 4)); // Calls the second method
        System.out.println("Sum of 2.5 and 3.5: " + math.add(2.5, 3.5)); // Calls the third method
    }
}

Example 2: Method Overloading with Different Parameter Types

class Display {
    
    // Method to display an integer
    void show(int a) {
        System.out.println("Integer: " + a);
    }
    
    // Method to display a string
    void show(String b) {
        System.out.println("String: " + b);
    }
    
    // Method to display a double
    void show(double c) {
        System.out.println("Double: " + c);
    }
}

public class Main {
    public static void main(String[] args) {
        Display display = new Display();
        
        display.show(10);          // Calls the integer method
        display.show("Hello");     // Calls the string method
        display.show(10.5);        // Calls the double method
    }
}

Example 3: Method Overloading with Different Number of Parameters

class Concatenator {
    
    // Method to concatenate two strings
    String concatenate(String a, String b) {
        return a + b;
    }
    
    // Method to concatenate three strings
    String concatenate(String a, String b, String c) {
        return a + b + c;
    }
}

public class Main {
    public static void main(String[] args) {
        Concatenator concat = new Concatenator();
        
        System.out.println(concat.concatenate("Hello, ", "World!")); // Calls the first method
        System.out.println(concat.concatenate("Java ", "is ", "fun!")); // Calls the second method
    }
}

Conclusion

Method overloading is a powerful feature in Java that enhances code readability and reusability. By allowing multiple methods with the same name but different parameters, developers can create more intuitive and flexible APIs.

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