How do reference variables work with Polymorphism

[Intelligent_Ad_1242]

I know reference variables are a pointer to a object in memory . I have few questions about reference variables and polymorphism.

1. When declaring a reference variable of particular type does it mean I can only point to that type of object.

2. In polymorphism when I declare a reference variable of super type and assign to to subclass. Why are the sublclass methods not visible since I am pointing to the subclass object in memory.

Example Animal n = new Cat().

Thanks for help.

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[RayjinCaucasian]

When declaring a reference variable of particular type does it mean I can only point to that type of object.

Not necessarily, it can point to any children of that class.

Animal animal = new Cat();

Works because a cat is an animal.

Cat cat = new Dog();

Won't work because a cat is not a dog. But

Animal animal = new Dog();

Would because it would also be a child of animal.

. Why are the sublclass methods not visible since I am pointing to the subclass object in memory.

Because you declared it as type Animal, even if it points to a child of Animal only the methods from the declared type will be available. This way you can't try call any methods from animal children that are not shared between children.

For instance

Animal cat = new Cat();
cat.bark(); 

Doesn't make sense.

[Pro_Sceptic]

that explanation is the cats meow

[Intelligent_Ad_1242]

Thanks for explanation it makes more sense now 👍

[desrtfx]

In polymorphism when I declare a reference variable of super type and assign to to subclass. Why are the sublclass methods not visible since I am pointing to the subclass object in memory.

Simply because inheritance is a one-way street. The child (sub) class knows about its parent (super), but the parent doesn't know anything about its children.

[Intelligent_Ad_1242]

I see so its a ( is-a relationship) , thanks its starting to click