Abstract class concept in Java

Concept :
we know object of abstract class can not be created. but when we create an obj
of subclass of abstract class then the constructer of super class must be run and since constucter run obj must be created then how can we say obj of abst class can not be created.

Explanation:

Regarding the Abstract Class problem, it's not that an object of an abstract class is never created. By saying that an object of an abstract classes can't be created we mean that they can't be created explicitly and independently. That means you can't have any code creating them independently.

But, as you have mentioned that while creating a subclass object the object of superclass is always created first and abstract classes are also no exceptions in this case. Otherwise you can't access the accessible members of an abstract superclass in an object of any of its subclasses. All right?

You might have noticed that any code trying to instantiate an abstract class explicitly throws a compile-time error, which means the compiler checks the corresponding classes for every direct instantiation and reports errors whenever it finds any of them being anything other than a concrete class. The error may be thrown if it's an abstract class or an interface or something of that sort. Right?

The moral is that the objects of abstract classes are certainly created (otherwise the whole concept of superclass-subclass object creation would go awry), but only implicitly :-)

What I understand is that this check is only at the compiler level, so what'll happen if somebody manages to temper the bytecodes somehow with the addition of direct instantiation code of an abstract class without disturbing the allowed bytecodes format (otherwise the Verifier component of Linker would throw an error)? I'm not sure if that's possible at all. The Verifier is quite conservative in nature and I believe it should be able to recognize even a slight bytecode tempering.