Method signature and overloading

Method signature

A method signature consists of:

• Method name
• Parameter types and order (number, types, and sequence)

It does NOT include:

• Return type
• Access modifiers
• Thrown exceptions

public int calculateSum(int a, double b) throws Exception { ... }
// Signature: calculateSum(int, double)

Method overloading

Defining multiple methods with the same name but different parameter lists (different signatures). Return type alone is not sufficient to overload.

Valid overloading:

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

Invalid overloading (only return type differs):

int process(int x) { ... }
double process(int x) { ... } // compilation error

Overloading with varargs:

void display(String s) { ... }
void display(String... args) { ... } // valid but ambiguous sometimes

Overloading and type promotion: Java chooses the most specific method.

void print(int i) { System.out.println("int"); }
void print(double d) { System.out.println("double"); }
print(5);      // calls int version
print(5.0);    // calls double version