java - Accessing specific ArrayList elements, when the ArrayList changes frequently -

i have arraylist stores object foo.

let's want add 10 of objects foo arraylist, following:

for (int = 0; <10 ; i++){     arraylist.add(new foo()); }

while solution works, problem is, how access, ninth foo, after third , fourth foo has been deleted away arraylist?

i cannot do

arraylist.get(9);

anymore, since throw indexoutofboundsexception.

i want able make program dynamically, since in case number of foos not fixed, , can deleted @ time.

you need have items in specific order , may not remember foo inserted @ index, map<integer, foo> perfect.

map<integer,foo> map = new hashmap<integer, foo>(); map.put(1, new foo()); map.put(2, new foo()); etc

per comments, map = treemap<integer, foo>() might better.

You