Interfaces - Beginning Java 8 Fundamentals - page 680

I1.m() and I2.m() . In this case, I2.m() is considered most specific as it overrides I1.m() . I will summarize this rule
as follows:

• Make a list of all choices of the method with the same signature that are available from

different superinterfaces.

• Remove all methods from the list that have been overridden by others in the list.

•
Consider the following Employee class. It implements Singer and SingerPlayer interfaces.

If you are left with only one choice, that is the method the class will inherit.

public class Employee implements Singer, SingerPlayer {
// Code goes here
}

There are no conflicts in inheriting the play() methods, which is inherited from the SingerPlayer interface.
There is no conflict in inheriting the sing() method as both superinterfaces leads to the same sing() method that is
in the Singer interface.
Which setRate() method is inherited by the Employee class? You have the following choices:
•

Singer.setRate()

SingerPlayer.setRate()
Both choices lead to an abstract setRate() method. Therefore, there is no conflict. However, the
SingerPlayer.setRate() method is most specific in this case as it overrides the Singer.setRate() method.
Which getRate() method is inherited by the Employee class? You have the following choices:
•

•

Singer.getRate()

SingerPlayer.getRate()
The Singer.getRate() method has been overridden by the SingerPlayer.getRate() method. Therefore,
Singer.getRate() is removed as a choice, which leaves you only one choice, SingerPlayer.getRate() . Therefore,
the Employee class inherits the default getRate() method from the SingerPlayer interface.

•

The Class Must Override the Conflicting Method
If the above two rules were not able to resolve the conflicting method's inheritance, the class must override the
method and choose what it wants to do inside the method. It may implement the method in a completely new way
or it may choose to call one of the methods in the superinterfaces. You can call the default method of one of the
superinterfaces of a class using the following syntax:

SuperInterfaceName.super.superInterfaceDefaultMethod(arg1, arg2...)

If you want to call one of the methods in the superclass of a class, you can use the following syntax:

ClassName.super.superClassMethod(arg1, arg2...)

Consider the following declaration for a MultiTalented class, which inherits from the Singer and Player interfaces:

// Won't compile
public abstract class MultiTalented implements Singer, Player {
}