About Arraylist declaration

#1

ArrayList arr=new ArrayList();
ArrayList arr=new ArrayList();
List arr=new ArrayList<>();

What is the difference in these declarations if any

#2

Two important concepts are involved in these declarations
1.Run time polymorphism
2. Generics in java

Please have a look into these concepts.
Now when a parent reference is pointing to child object like in case
List arr = new Arraylist<>()
Then on method calling through parent reference you have certain limitations.
Like you can call only overridden methods or methods of parent class.

Thanks

#3

Can u please explain in simple terms please I haven’t reached OOPS yet

#4

the difference between these two is of importance when you come to run time polymorphism. until then you can use any of them for your programs.
Thanks.

#5

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