Create an Array of Arraylists
As per Oracle Documentation:
"You cannot create arrays of parameterized types"
Instead, you could do:
ArrayList<ArrayList<Individual>> group = new ArrayList<ArrayList<Individual>>(4);
As suggested by Tom Hawting - tackline, it is even better to do:
List<List<Individual>> group = new ArrayList<List<Individual>>(4);
As the others have mentioned it's probably better to use another list to store the ArrayList in but if you have to use an array:
ArrayList<Individual>[] group = (ArrayList<Individual>[])new ArrayList[4];
This works:
ArrayList<String>[] group = new ArrayList[4];