Difference in Two ArrayList

#1

Mam is there any difference in the syntax of arrayList named baseResult(In Base Case) and myResult array list?

Difference -ArrayList<> myResult=new ArrayList();
ArrayList<> baseResult=new ArrayList<>();

#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.
always mention the type in arraylist everywhere to be sure and avoid errors
as
ArrayList<String> ans = new ArrayList<>();
Thanks