Hi Analise! Welcome to javaranch.
As far as your problem goes, is the code you put here exactly what you wrote. I feel that you named your own class as ArrayList.
This can be seen from your error too
AList.java:23: type ArrayList does not take parameters
List<Integer> iL = new ArrayList<Integer>();
^
.\ArrayList.java:22: incompatible types
found : ArrayList
required: java.util.List<java.lang.Integer>
List<Integer> iL = new ArrayList();
^
Note: Some input files use unchecked or unsafe operations.