Interface array in Java

I have an interface a:

interface A {
}

Then I have a level B:

class B implements A {
}

Then I have a way to use the a list:

void process(ArrayList<A> myList) {
}

I want to pass a B list:

ArrayList<B> items = new ArrayList<B>();
items.add(new B());
process(items);

But there is a type mismatch error I understand why ArrayList itself is a type. It has no function of converting from ArrayList < b > Go to ArrayList < a > Is there a quick and resource oriented way to form a new array suitable for the process methods passed to me?

Solution

I think the simplest solution is to change one of the methods to:

void process(ArrayList<? extends A> myList) {
}

Note, however, that when using this solution, the entire list must be of the same type That is, if you have a class C that also implements a, you can't mix the items in the array so that some of them belong to class B and some belong to class C

In addition, as noted in the comments below, you will not be able to add objects to the list in this method