Is It Possible To Instantiate An Abstract Bird Inwards Java?

Earlier I accept shared i of the often asked questions inwards Java, can nosotros brand an abstract degree in conclusion inwards Java in addition to my readers genuinely liked in addition to asked for to a greater extent than such questions. So, today I am going to utter close whether nosotros tin dismiss create an event of an Abstract degree inwards Java or not? This is closed to other interesting heart Java inquiry y'all volition detect on telephonic interviews or Oracle certified Java programmer certification. The respond to this inquiry is simple, No, y'all cannot instantiate an abstract degree inwards Java because it is abstract, it is non consummate thence it cannot endure used.  When y'all create an event of a class, its's constructor is called in addition to fifty-fifty though abstract degree tin dismiss accept a constructor, the compiler volition non allow y'all to create an event of the class. It's a compile-time mistake to create an event of an abstract degree inwards Java.

Let's run into closed to code representative to bear witness this indicate that it's illegal to create an event of an abstract degree inwards Java:

package tool;  /*  * Java Program to bear witness that y'all cannnot  * create event of an abstract degree  * inwards Java. fifty-fifty though y'all tin dismiss define  * constructor.  */ public class Hello {    public static void main(String[] args) {     Nested n = new Nested();   }    abstract class Nested {      public Nested() {       System.out.println("No-argument default constructor");     }   }  }

When y'all compile this degree using javac on the ascendancy business or simply type the code inwards Eclipse IDE, y'all volition run into next compile fourth dimension error:

Exception inwards thread "main" java.lang.Error: Unresolved compilation problem: 
at tool.Hello.main(Hello.java:15)

You tin dismiss run into that fifty-fifty though y'all tin dismiss declare constructor within an abstract class, equally before long equally y'all endeavor to instantiate an abstract class, the compiler is throwing "Cannot instantiate the type Hello.Nested" error.

This is truthful for both top aeroplane in addition to nested abstract degree inwards Java, y'all cannot extend whatsoever of them.

This is genuinely the follow-up of closed to other interesting heart Java question, can an abstract degree accept a constructor inwards Java. In the in conclusion post, I explained y'all close whether an abstract degree tin dismiss accept constructor or non in addition to if it's allowed so why practise y'all demand a constructor for an abstract degree which is incomplete.

The existent utilization of constructor inwards an abstract degree is to initialize the fields which belong to the abstract degree itself but constructor must endure invoked from a concrete subclass equally role of creating an event of a concrete subclass inwards Java.

Btw, if y'all are simply starting amongst Java so y'all should showtime banking enterprise tally out the Complete Java Masterclass on Udemy, i of the ameliorate course of written report to start amongst Java.

That's all close whether y'all tin dismiss instantiate an abstract degree inwards Java or not. As I said, Java specification doesn't allow y'all to create an object of an abstract class, it's a compile-time error, fifty-fifty though y'all tin dismiss accept constructor within the abstract class.

This sort of inquiry is real pop during a telephonic circular of interview equally good equally Java certification exams similar OCAJP8 in addition to OCPJP8 which often gives y'all code based upon this concept in addition to diverse choices similar what volition occur when y'all run this program.

You volition detect many such questions on pop mock bear witness simulators similar Whizlabs or David Mayer's Java 8 Exam Simulator.


Other interesting Core Java Articles in addition to Resources y'all may like
Can y'all brand a degree static inwards Java?
Can y'all run a Java programme without main() method?
Is Java top past times value or top past times reference?
Why Java doesn't back upwards multiple inheritances?
Why operator overloading is non supported inwards Java?
Java Basics: Learn to Code the Right Way

Thanks for reading this article so far, if y'all similar this tutorial so delight part amongst your friends in addition to colleagues. If y'all accept whatsoever questions or feedback so delight drib a comment.

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