Can Y'all Brand An Abstract Class/Method Concluding Inward Java?

No, you cannot brand an abstract course of report or method terminal inwards Java because the abstract too terminal are the mutual exclusive concept. An abstract course of report is incomplete too tin entirely hold out instantiated yesteryear extending a concrete course of report too implementing all abstract methods, spell a final class is considered every bit consummate too cannot hold out extended further. This way when you lot brand an abstract course of report final, it cannot hold out extended thus it cannot hold out used too that's why Java compiler throws a compile-time fault when you lot effort to brand an abstract class terminal inwards Java. In short, an abstract course of report cannot hold out terminal inwards Java, using both abstract too final modifier amongst a course of report is illegal inwards Java.

Same is truthful for abstract methods, you lot cannot brand the terminal inwards Java. An abstract method must hold out overridden to hold out useful too called but when you lot brand the abstract method terminal it cannot hold out overridden inwards Java, thus in that place would hold out no way to role that method.

This is why making an abstract method final inwards Java volition number inwards a compile-time error. In short, the role of keywords abstract too final together is illegal inwards Java. You tin verify these facts yesteryear yourself yesteryear trying to brand an abstract class/method terminal inwards Java. In this article, I'll exhibit you lot an event of both to seek out the higher upwardly points.

Even though it may seem slowly that both these concepts are mutually exclusive, many Java programmers acquire confused betwixt them. They simply don't sympathise that abstract way incomplete too final way complete, too how a matter tin hold out both consummate too incomplete at the same time? It's simply a mutual feel 1 time you lot know the concept inwards depth.

Btw, if you lot are novel into Java globe or self-learning Java so I advise you lot to besides bring together The Complete Java Masterclass on Udemy. One of the most comprehensive too up-to-date courses inwards Java. It is latterly updated for Java 12 too I highly recommend to all my readers to larn Java or create total gaps inwards their learning.

Can nosotros brand an Abstract course of report terminal inwards Java?

There is a maxim inwards Hindi, "Haath Kangan ko Aarshi Kya, Padhe Likhe ko Pharsi kya", which way instead of saying simply show. So, why non nosotros instead of saying that whether nosotros tin brand an abstract terminal inwards Java or not, simply code it too come across what happens.

Let's effort that, the next is a sample code which uses both abstract too final modifier together at course of report declarations when you lot write this code inwards Eclipse, the IDE volition advise this is incorrect yesteryear giving an fault every bit shown below:

abstract final class ImAnAbstractClass{  }

Error: "The course of report ImAnAbstractClass tin hold out either abstract or final, non both"

Unlike many others, this fault is both clear too concise too shows that it's non possible to brand a course of report both terminal too abstract at the same fourth dimension inwards Java.

Btw, If you lot compile higher upwardly Java source file using Java compiler (javac) from the dominance trace you lot volition have a similar error. Eclipse uses slightly dissimilar compile but it follows almost all rules of Java compiler.

If you lot desire to larn to a greater extent than well-nigh what rules Java compiler follows or to a greater extent than of such telephone commutation concepts, you lot tin besides join abstract course of report final inwards Java, let's effort to brand an abstract method terminal inwards Java. As I said above, this fourth dimension besides Java compiler should complain because both final too abstract are mutual exclusive keywords:

abstract class ImAbstract{  public final abstract void anAbstractMethod(); }  class ImConcrete extends ImAbstract{  @Override public void anAbstractMethod() { // TODO Auto-generated method stub  }  }

This volition laissez passer the fault "The abstract method anAbstractMethod inwards type ImAbstract tin entirely prepare a visibility modifier, 1 of populace or protected" when you lot write this code inwards Eclipse, every bit shown inwards the next screenshot:

You volition besides have the fault "Cannot override the terminal method from an abstract" on the subclass, every bit shown inwards the next screenshot which shows cannot override the terminal method from an abstract class.

This makes it clear that it's non possible to brand a course of report both abstract too terminal inwards Java. It's 1 of the telephone commutation concepts and  If you lot desire to larn to a greater extent than well-nigh Java fundamentals, I advise you lot read a expert substance Java mass like Core Java For the Impatient by Cay. S. Horstmann.

That's all well-nigh whether you lot tin brand an abstract class/method terminal inwards Java or not. The brusk respond is no, you lot cannot brand the terminal too long respond is what I convey explained inwards this post. Since abstract too terminal stand upwardly for ii mutually exclusive concepts they cannot hold out used together.

Some of you lot mightiness hold out wondering well-nigh variables? Can nosotros brand a terminal variable abstract inwards Java? Well, a variable cannot hold out abstract inwards Java. The role of abstract keyword is illegal for a variable, it tin entirely hold out used amongst course of report or method, thus in that place is a way you lot tin brand a terminal variable abstract inwards Java.


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Thanks for reading this article, If you lot similar this interview query too my explanation so delight portion amongst your friends too colleagues. If you lot convey whatever query or feedback so delight driblet a comment.

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