在Java中重载和重写

Question

I know how to overload a method, and how to override a method. But is that possible to overload AND override a method at the same time? If yes, please give an example.

Answer 1

Overloading and overriding are complementary things, overloading means the same method name but different parameters, and overriding means the same method name in a subclass with the same parameters. So its not possible for overloading and overriding to happen at the same time because overloading implies different parameters.

Examples:

class A {
    public void doSth() { /// }
}

class B extends A {
    public void doSth() { /* method overriden */ }

    public void doSth(String b) { /* method overloaded */ }

}

Cheers!

Answer 2

overloading and overloading are just abstractions. Overloading just means the compiler uses the name in conjunction with the types and number of parameters for addressing what function to call. In reality overloading a method is no different than naming it something different because the key the compiler uses to look up the function is a combination of name and parameter list.

Overriding is kind of the same principle except the compiler can address the overriden function with the super keyword.

So can you override an overloaded function? Yes, since the overloaded method is a completely different method in the eyes of the compiler.

Answer 3

It depends what you mean. A method can be an override for an overloaded method in a superclass. And you can overload a method that you are simultaneously overriding using another method.

However, you cannot have one method that is both a new overload and an override. For a method to be an override, another method with the same signature must already exist in the superclass ... and that means that this method cannot be a new override.