Question

I have three interfaces as follows.

interface CFL extends PowerSaver, LightingDevice{
    void showLifeTime();
    void getBrand();
}

interface PowerSaver {
    void showEcoRate();
}

interface LightingDevice {
    void doLight();
}

Then I create a abstract class called Philips that implements CFL

public abstract class Philips implements CFL{
    void showLifeTime(){}; // Compiler says Cannot reduce the visibility of the inherited method from CFL.
    void showEcoRate(){};  // Compiler says Cannot reduce the visibility of the inherited method from CFL.
}

My question is why it says that I Cannot reduce the visibility of the inherited method from CFL. while I haven’t reduced it?

Answer 1

Interface implementations must be public.

To understand the error, see the spec:

Every method declaration in the body of an interface is implicitly public.

Therefore, you’re actually overriding (or, in this case, implementing) public methods.