javamemory-managementupcasting

memory allocation for upcasting in java

Considering these classes:

public class Animal{

}

public class Dog extends Animal{

}

public AnimalTest(){
    public static void main(String[] args){
       Dog d = new Dog();
       Animal a = d;
   }
}

my question is since I performed an upcasting on Animal a = d;does it consume a new memory allocation on the machine or does it use the memory allocated to the Dog d = new Dog();

Solution

  • Animal a = d;

    a is just a reference and the reference's memory is allocated in method stack(or jvm stack, not heap).

    That is when invoke the method main, JVM will allocate a stack which contains the reference's space.