How to move specific item in array list to the first item

Question

For example : A list

A B C D E

Given C , Switch to

C A B D E

Notice that the array size will change, some items may removed in run times

Answer 1

This code will allow you to increase size of list, and insert elements without otherwise disturbing order of list

private void insert(double price){
    for(int i = 0; i < keys.size(); i++){
        if(price > keys.get(i)){
            keys.add(null);
            for(int j = keys.size()-1; j > i; j--){
                Collections.swap(keys, j, j-1);
            }
            keys.add(price);
            Collections.swap(keys, keys.size()-1, i);
            keys.remove(keys.size()-1);
            return;
        }
    }
    keys.add(price);
}