Since it only extends B however, it only needs to implement B abstract methods and unimplemented interfaces. 
treat the function, as an invoked function of the interface or the abstract class ? so that makes it mandatory for class C to implement the abstract class's version of doStuff() instead of the interface's ? I think that the explanation that you are looking for can be found here. Which should look familiar, as Abstract Class B has the same method signature. to variables of type of the abstract class or interface if you just implement the interface on your abstract class. from interface or abstract class? While looking at some OOP materials, I thought of this question which confused me a little bit: Consider having the following interface,abstract class, and a concrete class: Class C won't compile unless it provides an implementation for method doStuff(). So, what would it look like for the JVM when it invokes the function? How should we do boxplots with small samples? Thanks for contributing an answer to Stack Overflow! And if you want to implement difference methodbetween them. In fact there is no difference for user, whether C.doStuff() overrides B's method or A's. Why did the gate before Minas Tirith break so very easily? Trending is based off of the highest score sort and falls back to it if no posts are trending. Is there a political faction in Russia publicly advocating for an immediate ceasefire? Question 2: It is not considered an implementation. Short story about the creation of a spell that creates a copy of a specific woman. Implementation in class C is mandatory (even if you don't have the abstract one in class B). Abstract classes do not have to implement all interfaces methods. Please be so kind to close your Threads when you found an answer, these Threads should help everyone with similar issues. so, will the JVM invoke the function as an implementation for interface A or abstract class B ? For Question #1: The doStuff method in class C is the implementation of the doStuff method declaration to both B and C. because the doStuff method declaration in abstract class B and interface A has the same signature as each other. 
Why does KLM offer this specific combination of flights (GRU -> AMS -> POZ) just on one day when there's a time change? can i use division when im inducting a proof? 
Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. You can mark your own posts as answers if you were not helped out but found a solution, in such a case, please provide the answer. Difference between abstract class and interface in Python. You can now choose to sort by Trending, which boosts votes that have happened recently, helping to surface more up-to-date answers. RJP1973 mentioned. what if class B without implements Abut has it's own abstract doStuff() method ? In your abstract class, then the childs that inherits this class HAVE TO implement this method. In an interface, all methods are public and abstract. This forum has migrated to Microsoft Q&A. Why dont second unit directors tend to become full-fledged directors? from interface or abstract class? 
To learn more, see our tips on writing great answers. Find centralized, trusted content and collaborate around the technologies you use most. Although this kind of situation sounds like a highly confusing and unnecessary one that should be avoided if at all possible. US to Canada by car with an enhanced driver's license, no passport?
Why is the US residential model untouchable and unquestionable? When to use an interface instead of an abstract class and vice versa? How should I have explained the difference between an Interface and an Abstract class? Data Imbalance: what would be an ideal number(ratio) of newly added class's data?
How does a tailplane provide downforce if it has the same AoA as the main wing? Implementing multiple interfaces having same method. Because the class just has only one parent class. MSDN Support, feel free to contact MSDNFSF@microsoft.com. Knowing this, interface A's doStuff is actually public abstract void doStuff(). Site design / logo 2022 Stack Exchange Inc; user contributions licensed under CC BY-SA. rev2022.7.21.42639. Making statements based on opinion; back them up with references or personal experience. to be more specific: How will the JVM If you use potential fixes feature. Can an abstract class have a constructor? Which one should be implemented? Please remember to click "Mark as Answer" the responses that resolved your issue, and to click "Unmark as Answer" if not. Basically, the abstract class is a kind of template containing high-level logic for the convenience of its subclasses.
Overriding the method upPoint in Program would only need to be done once, and this would satisfy both requirements to implement the abstract ancestor method and the interface method. you will see theVS just generate only one method. Actually, if B implements C, there is no need to declare doStuff method again. 
Suppose one method is the same in interface and abstract and one class derived from these(interface and abstract). Is there a difference between truing a bike wheel and balancing it? 
will it invoke it as a function of the interface or as a function of the abstract class ? Try to remove this method in Class B and see the results in class C, See section When an Abstract Class Implements an Interface in http://docs.oracle.com/javase/tutorial/java/IandI/abstract.html. Connect and share knowledge within a single location that is structured and easy to search. You can close a Thread via the"Mark as Answer" link below posts. Sum of Convergent Series for Problem Like Schrdingers Cat. When to use: Java 8+ interface default method, vs. abstract method. if B has no method implementation or additional method declaration, it is needless of class B. If that doesn't work for you, you can implement interface methods explicitly by preceeding the method name with the interface name and ".". If you run the below code, you will get the same result. Sounds to me like you have a design flaw. Asking for help, clarification, or responding to other answers. If either ofthem is not implemented, the compiler will prompt the unrealized message and of course the program can't pass to build. For instance of class B, C.doStuff() overrides B.doStuff() and implements A.doStuff(). You will be able to assign objects from those derived classes
To answer question 1, class B's doStuff() is the same as interface A's doStuff(). To subscribe to this RSS feed, copy and paste this URL into your RSS reader. What are the purpose of the extra diodes in this peak detector circuit (LM1815)? PS: I assure everyone that I did not ever had the desire to offend anyone. For Question #2: No, the doStuff in B is just a declaration, not a method implementation. All methods in java are invoked virtually. Show that involves a character cloning his colleagues and making them into videogame characters?