2.11 Method Overloading

Learning Objectives

•Define multiple overloaded versions of a method or constructor.
•Explain how Java chooses which overload to invoke.
•Distinguish overloading (same name, different parameters) from overriding (Chapter 3).

Introduction

Method overloading lets a class define multiple methods with the same name, as long as their parameter lists differ (in number, type, or order). The compiler picks the correct overload to call based on the arguments provided at the call site — this is resolved at compile time, not runtime.

Key Concepts

Overloads must differ in their parameter list — return type alone is not enough to distinguish them.

The compiler selects an overload based on the number, types, and order of arguments at the call site.

Constructors can be overloaded too, letting objects be created in more than one way.

Java Syntax

Code Examples

Three `add` overloads share a name but differ in parameter count/type. Java selects the matching overload for each call based on the arguments' types.

Common Mistakes

⚠Trying to overload two methods that differ only in return type — this is a compile error.
⚠Expecting overload resolution to happen at runtime based on actual object type — it's determined at compile time from the declared argument types (contrast with overriding in Chapter 3).

Practice

Practice 1

Multiple Choicemedium

Which change alone is enough to legally overload a method?

Changing only the return type

Changing only the access modifier

Changing the number or types of parameters

Changing only the method body

Summary

Overloading lets one method name serve several parameter signatures; the compiler picks the right one at compile time based on the call's arguments.

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