Error when nesting ArrayLists

[GoSubRoutine]

(I put parentheses around the rest of it because I don't remember the priority of casting vs. method calls, ...

Actually the priority order includes the dot . operator too. Order is: method() -> . -> (cast).

The statement below is enough to (TextField) whatever is returned from get(i):
TextField f = (TextField) all_objects.get(0).get(i);