Programming Fundamentals › Object-Oriented Programming

Method Overloading

Several methods with the same name but different parameters.

Also known as: function overloading, overloaded methods, overloading

Method overloading is defining several methods with the same name but different parameters. The compiler picks the right one from the arguments at the call.

class Printer {
    void print(int n)        { System.out.println("int " + n); }
    void print(String s)     { System.out.println("string " + s); }
    void print(String s, int times) { ... }
}

printer.print(5);            // calls the int version
printer.print("hi");         // calls the String version

Java, C#, C++ and Kotlin support it. It lets one concept have convenient forms without inventing names like printInt and printString.

Languages without it

Python and JavaScript don’t have overloading, since a name refers to one function. People use other tools:

def print_value(value, times=1):          # default arguments
    ...

def print_value(*args): ...               # variable arguments
def parse(x):
    if isinstance(x, str): ...            # check types inside

TypeScript lets you declare several signatures, with a single implementation.

Not the same as overriding

• Overloading: same class, same name, different parameters, chosen at compile time.
• Overriding: a subclass replaces a parent’s method with the same signature, chosen at run time (method overriding).

Cautions

• Too many overloads confuse callers. Ask whether differently named methods would be clearer.
• Ambiguous calls happen when null or numeric conversions could match several versions.
• Default parameters or a builder often replace long chains of overloads (default parameters).