🧠 Java Method Overloading – Same Method Name, Different Parameters

Method overloading in Java is a powerful feature of polymorphism that allows a class to have more than one method with the same name, differentiated by parameter type, number, or order. It helps in increasing the readability and reusability of code by performing similar operations with different input values.

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✅ What is Method Overloading?

Method Overloading is when multiple methods in the same class have the same name but differ in:

• Number of parameters
• Type of parameters
• Order of parameters

📌 It is resolved at compile time, also known as compile-time polymorphism.

class Calculator {
    int add(int a, int b) {
        return a + b;
    }

    double add(double a, double b) {
        return a + b;
    }

    int add(int a, int b, int c) {
        return a + b + c;
    }
}

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✅ Rules of Method Overloading

1. 🔁 Methods must have different parameter lists.
2. 🧩 It can differ by:
   • Number of parameters
   • Data types of parameters
   • Order of parameters (only if types differ)
3. ❌ Return type alone cannot be used to distinguish overloaded methods.

// Invalid overloading (only return type differs)
int sum(int a, int b) { return a + b; }
// double sum(int a, int b) { return a + b; } // ❌ Compile-time error

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✅ Why Use Method Overloading?

• 🚀 Improves code readability
• 🔁 Reduces method naming clutter
• 📦 Handles various types of inputs elegantly
• ♻️ Encourages code reusability

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✅ Examples of Overloading

1. By Changing Number of Arguments

class Printer {
    void print(String msg) {
        System.out.println(msg);
    }

    void print(String msg, int times) {
        for (int i = 0; i < times; i++) {
            System.out.println(msg);
        }
    }
}

2. By Changing Data Type of Arguments

class Area {
    void calculate(double radius) {
        System.out.println("Circle Area: " + (Math.PI * radius * radius));
    }

    void calculate(double length, double width) {
        System.out.println("Rectangle Area: " + (length * width));
    }
}

3. By Changing Order of Arguments

class Display {
    void show(String name, int age) {
        System.out.println("Name: " + name + ", Age: " + age);
    }

    void show(int age, String name) {
        System.out.println("Age: " + age + ", Name: " + name);
    }
}

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✅ Method Overloading with Type Promotion

When an exact match isn’t found, Java promotes smaller data types:

class Demo {
    void test(int a, double b) {
        System.out.println("int-double");
    }

    void test(double a, int b) {
        System.out.println("double-int");
    }

    public static void main(String[] args) {
        Demo d = new Demo();
        d.test(10, 20); // int promoted to double for the second method
    }
}

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✅ Constructor Overloading

Java also allows overloading constructors to initialize objects differently:

class Book {
    String title;
    int pages;

    Book(String t) {
        title = t;
        pages = 100;
    }

    Book(String t, int p) {
        title = t;
        pages = p;
    }
}

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✅ Overloading vs Overriding

Feature	Overloading	Overriding
👥 Scope	Same class	Subclass
🔁 Method Signature	Varies	Must be same
⚙️ Type	Compile-time	Run-time
♻️ Return Type	Can vary	Should be same/subtype
🧠 Inheritance	Not required	Required

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⚠️ Common Mistakes and Best Practices

❌ Common Mistakes:

• Thinking return type alone can overload a method.
• Forgetting that parameter names don’t matter for overloading.
• Relying too much on type promotion can lead to ambiguity.

✅ Best Practices:

• Keep method behavior consistent with the name.
• Avoid excessive overloading; use default values if appropriate.
• Document clearly when multiple overloaded methods are available.

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🧾 Summary: Java Method Overloading

✅ Key Takeaways
Method Overloading allows methods with same name but different parameters.
It improves code readability and supports polymorphism.
Java supports overloading with data type, number, or order of parameters.
Return type cannot be the only difference.
Constructor overloading works the same way.

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❓ FAQs: Java Method Overloading

Q1: Can two methods with the same name and parameters but different return types coexist?

A: No, return type alone isn’t enough for overloading.

Q2: Is method overloading possible across different classes?

A: No, overloading happens in the same class. Across classes is overriding.

Q3: Is method overloading polymorphism?

A: Yes, it is a form of compile-time polymorphism.

Q4: Can constructors be overloaded?

A: Yes, constructors can be overloaded in the same class.

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