Java Method Overloading

Multiple methods with the same name

🔄 What is Method Overloading?

Method overloading allows multiple methods with the same name but different parameters. Java chooses the correct method based on the arguments you provide when calling it. 


// Same method name, different parameters
public static void print(String text) { }
public static void print(int number) { }

Java automatically picks the right method:

print("Hello") → calls String version

print(42) → calls int version

Key Overloading Concepts

📝

Same Name

All methods have identical names 

void calculate() { }
void calculate(int x) { }
🔢

Different Parameters

Methods differ by parameter count/type 

void method(int a) { }
void method(String b) { }
🎯

Automatic Selection

Java picks the right method automatically 

method(5);     // calls int version
method("hi");  // calls String version
♻️

Code Reuse

Same functionality, different inputs 

add(2, 3);
add(1.5, 2.7);

🔹 Basic Overloading Example

Multiple methods with the same name but different parameter types: 

public class OverloadingExample {
    
    // Method 1: Print string
    public static void display(String message) {
        System.out.println("String: " + message);
    }
    
    // Method 2: Print integer
    public static void display(int number) {
        System.out.println("Integer: " + number);
    }
    
    // Method 3: Print double
    public static void display(double decimal) {
        System.out.println("Double: " + decimal);
    }
    
    public static void main(String[] args) {
        display("Hello World");  // Calls String version
        display(42);             // Calls int version
        display(3.14);           // Calls double version
    }
}

Output:

String: Hello World

Integer: 42

Double: 3.14

🔹 Different Number of Parameters

Overloading by changing the number of parameters: 

public class Calculator {
    
    // Add two numbers
    public static int add(int a, int b) {
        return a + b;
    }
    
    // Add three numbers
    public static int add(int a, int b, int c) {
        return a + b + c;
    }
    
    // Add four numbers
    public static int add(int a, int b, int c, int d) {
        return a + b + c + d;
    }
    
    public static void main(String[] args) {
        System.out.println("2 + 3 = " + add(2, 3));
        System.out.println("1 + 2 + 3 = " + add(1, 2, 3));
        System.out.println("1 + 2 + 3 + 4 = " + add(1, 2, 3, 4));
    }
}

Output:

2 + 3 = 5

1 + 2 + 3 = 6

1 + 2 + 3 + 4 = 10

🔹 Mixed Parameter Types

Overloading with different combinations of parameter types: 

public class PersonInfo {
    
    // Method 1: Name only
    public static void createProfile(String name) {
        System.out.println("Profile: " + name);
    }
    
    // Method 2: Name and age
    public static void createProfile(String name, int age) {
        System.out.println("Profile: " + name + ", Age: " + age);
    }
    
    // Method 3: Name, age, and student status
    public static void createProfile(String name, int age, boolean isStudent) {
        System.out.println("Profile: " + name + ", Age: " + age + ", Student: " + isStudent);
    }
    
    // Method 4: Age and name (different order)
    public static void createProfile(int age, String name) {
        System.out.println("Profile (age first): " + name + ", Age: " + age);
    }
    
    public static void main(String[] args) {
        createProfile("Alice");
        createProfile("Bob", 25);
        createProfile("Charlie", 20, true);
        createProfile(30, "Diana");
    }
}

Output:

Profile: Alice

Profile: Bob, Age: 25

Profile: Charlie, Age: 20, Student: true

Profile (age first): Diana, Age: 30

🧠 Test Your Knowledge

What makes method overloading possible in Java?