When we create a Subclass object which extends an abstract class, the abstract class constructor also runs . But we know we cannot create objects of an abstract class. Hence
Barring any exceptions, the abstract class constructor is only run from within the subclass's constructor (as the first statement). Therefore you can be sure that every time a constructor is run, it is in the process of creating an object.
That said, you may call more than one constructor in the process of creating a single object, such as Subclass() calling Subclass(String) which calls AbstractClass via a super()call, and so forth.