Is It Possible To Convey An Abstract Method Inwards A Lastly Class?

This is i of the interesting meat Java questions which was asked to i of my readers latterly during a telephonic interview for Java developer project interview. Even though he knows that you lot cannot brand an abstract flat lastly inward Java, he got confused past times the wording of the methods. The respond is simple, No, it's non possible to convey an abstract method inward a lastly flat inward Java. Why? because equally before long equally you lot declare an abstract method inward a Java class, the flat automatically becomes an abstract flat in addition to you lot cannot brand an abstract flat final inward Java equally discussed before, thus it's non possible to convey an abstract method inward a lastly flat inward Java.

Many Java programmers acquire confused inward this query simply because of the wording of the question, equally I said, fifty-fifty the reader who was asked this query was familiar alongside the concept, he didn't realize that equally before long equally you lot declare an abstract method inward a class, it volition drib dead an abstract flat in addition to it's non possible to brand an abstract flat lastly inward Java.

This is the missing slice of information or you lot telephone scream upwardly it a play a joke on which separates it from the to a greater extent than pop in addition to oft asked questions, can you lot declare a flat both abstract in addition to lastly inward Java?

Let's encounter i code illustration to seek this call for that you lot cannot declare an abstract method inward a lastly class. We convey a world lastly flat called Hello which has an abstract method called print() inward Hello.java file.

public final class Hello {    public abstract print();  }

As before long equally you lot type that inward your Eclipse IDE, you lot volition have next error:
The type Hello must live an abstract flat to define abstract methods



Here is about other screenshot which shows that you lot cannot convey an abstract method inward a lastly flat inward Java:

Same is truthful when you lot write downwardly this code inward notepad in addition to compile it using javac from the command-line window. As per Java specification, i time you lot declare an abstract method within a class, it automatically becomes an abstract flat in addition to since you lot cannot brand an abstract flat lastly inward Java, the compiler volition throw an error.

This is truthful for both transcend flat or nested flat inward Java. Even if declare an abstract method on a nested lastly class you lot volition have the same error.

Another follow-up query on this topic is can an abstract flat convey static methods inward Java? The respond is yes, at that spot is no work alongside declaring a static method within an abstract flat inward Java because you lot don't demand to instantiate a flat to role the static method, you lot tin simply telephone scream upwardly them past times using the flat name.


We tin alter our code illustration to include the main() method inward the Hello class, which is a static method inward Java equally shown below:

public abstract class Hello {    public abstract void print();    public static void main(String args[]) {      .. about code hither   }  }

You tin encounter that at that spot is no compile fourth dimension error. The code compiles fine, thus it is perfectly ok to declare a static method within an abstract class inward Java.


That's all nearly whether it's possible to convey an abstract method inward a lastly flat or not? As I said it's non possible because i time you lot create an abstract method within a class, equally per Java specification the flat automatically becomes an abstract class. Since you lot cannot brand a lastly flat abstract inward Java, this becomes illegal in addition to compiler prohibits you lot from doing that past times throwing an error. But, yes, you lot tin declare static methods on both lastly flat equally good equally abstract classes, at that spot is no work alongside that. If you lot are learning Java, I propose you lot farther read Core Java for Impatient to acquire yourself familiar alongside meat concepts similar abstract in addition to lastly class. It likewise covers Java 8.


Other related Java Interview Questions for practice

1. Can abstract flat convey a constructor inward Java? (answer)
2. Can you lot override a static method inward Java? (answer)
3. Can you lot overload a static method inward Java? (answer)
4. Can you lot run a programme without main() method inward Java? (answer)
5. Can you lot override a someone method inward Java? (answer)
6. Can you lot overload in addition to override the main() method inward Java? (answer)
7. Can you lot brand array volatile inward Java? (answer)
8. Can you lot declare a flat static inward Java? (answer)

Further Reading
Java Fundamentals, Part 1 in addition to ii
Java Programming Interview Exposed
Cracking the code interview - 189 qustions in addition to solutions

Thanks for reading this article, if you lot similar this meat Java interview query in addition to my explanation in addition to so delight percentage alongside your friends in addition to colleagues. 

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