CODE EXAMPLE FOR JAVA

site:stackoverflow.com List is abstract; cannot be instantiated public List result = new List<>();

In Java, List is an interface. That is, it cannot be instantiated directly.

Instead you can use ArrayList which is an implementation of that interface 
that uses an array as its backing store (hence the name).

Since ArrayList is a kind of List, you can easily upcast it:

List<T> mylist = new ArrayList<T>();

-source: stackoverflow.com