Eclipse message saying List cannot be resolved to a type

eclipse, java

Solution

You can press Shift+Ctrl+O for auto importing.

Problem

I am trying the following code in eclipse: ``` public class A { List<Integer> intList = new ArrayList<Integer>(); } ``` However it gives me an error saying: List cannot be resolved to a type and ArrayList cannot be resolved to a type. Is there some library I need to add and how do I do that?

Original source