Overloading method

Overloading method

There is no polymorphism involved here. Overloading means having 2 methods with same name but different argument list.

Overloading lets you make multiple versions of a method, with different argument lists, for convenience to the callers. For example, if you have a method that takes only an int, the calling code has to convert, say, a double into an int before calling your method. But if you overloaded the method with another version that takes a double, then you’ve made things easier for the caller.

public class Overloads {
    String uniqueID;
    public int addNums(int a, int b) {
        return a + b;
    }
    public double addNums(double a, double b) {
        return a + b;
    }
    public void setUniqueID(String theID) {
        // lots of validation code, and then:
        uniqueID = theID;
    }
    public void setUniqueID(int ssNumber) {
        String numString = "" + ssNumber;
        setUniqueID(numString);
    }
}

1) return types can be different 2) but you can’t change ONLY the return type

If only the return type is different, it’s not a valid overload—the compiler will assume you’re trying to override the method. And even that won’t be legal unless the return type is a subtype of the return type declared in the superclass. To overload a method, you MUST change the argument list, although you can change the return type to anything.

3) You can vary the access levels in any direction.

You’re free to overload a method with a method that’s more restrictive. It doesn’t matter, since the new method isn’t obligated to fulfill the contract of the overloaded method.