Enthuware

For the people who don't understand (like me) without a proper explanation (that is omitted by EthuWare):

The method of Office is static. It can only be referenced in a Static way: Office.getAdress().

Also, both interfaces can be extended by WHF because static is not the same as default.

The following detailed explanation is already provided:

Since the declared type of variable off is Office, compiler will check the call to getAddress against Office interface. However, getAddress in Office is static and Java 8 requires static interface method to be invoked using the interface name instead of a reference variable. That is why, the compiler will raise the following error message:
TestClass.java:26: error: illegal static interface method call     System.out.println(h.getAddress()); //2
                                   ^   the receiver expression should be replaced with the type qualifier 'Office' 1 error

Please let us know if you are not seeing this explanation.

The explanation was not visible to me because I used the wrong layout for Mac. Also, I am still getting this question wrong after one week now...

I think it is also worth pointing out that static *interface* methods are *not* redeclared + hidden as it would be the case with classes:
https://stackoverflow.com/questions/251 ... ic-methods

So Office.getAddress() does not conflict with the default method of the same name in the House interface.

So a static method in an interface always stays there and does never appear somewhere else. I wasn't aware of that.

@Samba2, that's what I was also looking at. Look at the code below. In the Interface Sub, the static method creates a problem and probably it is because the default method is inherited although the static one is not. But I wonder what is the point of remembering all these weird combinations people should not use in real life.

interface Super {
static void meth(){ }
}

interface Super2 {
default void meth(){ } // this is fine because meth() from Super is not inherited
}

interface Sub extends Super, Super2 {
static void meth(){} // this will not compile because meth() from Super2 is inherited
}