nakt
Answered On : Nov 20th, 2005
Why not ? Abstract classes are those classes where we do not want them to be instantiated and possibly all methods are not clear by the time when the abstreact classes are defined. But the abstract classes are used while the classses of the systen are refined, reshaped. The abstract class has the common data which can be constant or need to be set by the subclasses based on the specialisation . Therefore the subclass may want to set the abstracr classes variables as and when the subclass is created . Therefore the constuctor should be used in such a case.The jvm creates first the super class and then subclass on newing of the subclass
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Srinivasa Rao Goineni
Answered On : Sep 22nd, 2006
Hi,
We can't make constructor as abstract in an abstract class.Constrctor won't be inherited from base class to subclass.
Thanks
Srinivas gogineni
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biju
Answered On : Jan 17th, 2007
we can provide constructor to abstract class. this is for inheritance (for extended classes). This constructor can be invoked by subclasses. But new cannot be used.
public abstract class ABS{
public ABS(){
System.out.println("constructor ABS");
}
public abstract void m1();
}
public class ABS1 extends ABS{
public ABS1(){
super();
}
public void m1(){
}
public static void main(String[] args){
System.out.println("ABS1");
new ABS1();
}
}
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We can't make constructor as abstract in an abstract class.Constrctor won't be inherited from base class to subclass.
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An abstract class can always have a constructor for a reason that an abstract class even though cannot be instantiated but it can be extended. Once its extended by its subclass. the object of the subclass can be instantiated. Incase of constructors its first calls this() or super() sothe constructor of the base class is called finally till the control reach the Object class constructor. Once the constructor of the Object class completes the control goes to its child class which in its case can be an abstract class. hence further on the control reaches to the constructor of the child class (of the abstract class). hence we can say that there is a need for the constructor of the abstract class
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Yes, abstract classes may contain constructors reason is:
abstract classes may contain variables to instantiate those variables we use constructors.
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akash
Answered On : Aug 10th, 2012
Any class be it abstract or not, has a default constructor created by the jvm.
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