Trying to assign a superclass reference variable to subclass reference variable (child=parent)...is said to be downcasting...and it is possible at run time...
And you have to rememmber :
downcasting an superclass reference variable to an subclass reference
variable is possible only... if the super class variable actually refers to an instance of subclass or an subclass of the subclass....down the hierarchy...
Hope U clear now..
Cheers...