Object <? implements InterfaceA, InterfaceB>

Question

I need a object who refers to two diffenrent interfaces like this:

interface InterfaceA {
    public void a();
}

interface InterfaceB {
    public void b();
}

class Test() {
    Object <? implements InterfaceA, InterfaceB>; object;

    Test() {
        object.a();
        object.b();
    }
}

I know for inheritance there is this way: Class <? extends Main> a Class <? extends Main> a and a solution could be a helper class: class Helperclass implements InterfaceA, InterfaceB{}

Thanks for help and reading :)

Answer 1

If you add a generic type parameter to your Test class, you can require that this type parameter implement both interfaces:

class Test<T extends InterfaceA & InterfaceB> {
    T object;

    Test() {
        object.a();
        object.b();
    }

}

Of course you should initialize the object variable before calling methods.