Stack to --> ArrayList Java

Question

I made a Stack and an ArrayList to make a research. Actually I want now to make my Stack replaced by an ArrayList, but how to transform a Stack into an ArrayList ? How is it going with push, pop ... ?

Thank you

public static ArrayList<State> search(State finalstate)
{
    ArrayList<State> toreturn = new ArrayList<State>();
    Stack<State>mystack=new Stack<State>();
    mystack.push(initState);
    State currState;
    currState=initState;
    while(!mystack.isEmpty() && !currState.equals(finalstate) )
    {
        currState=mystack.pop();
        toreturn.add(currState);
        if(currState.vecinos.containsKey("up"))
        {
            mystack.push(currState).vecinos.get("up");
        }
        if(currState.vecinos.containsKey("down"))
        {
            mystack.push(currState).vecinos.get("down");
        }
        if(currState.vecinos.containsKey("left"))
        {
            mystack.push(currState).vecinos.get("left");
        }
        if(currState.vecinos.containsKey("right"))
        {
            mystack.push(currState).vecinos.get("right");
        }
    }

    return toreturn;
}

Answer 1

Stack is a Collection, you can use ArrayList(Collection) constructor

list = new ArrayList(stack);

Answer 2

The simplest way I've found to convert a Stack into a List is using the following line:

List<Integer> stackToList = new ArrayList(stack);

However, this yields the stack reversed. Meaning, if your stack was 1, 2, 3 you would expect in the list 3, 2, 1 because that's the order the stack objects would be "popped". That's not the case though instead, you get 1, 2, 3. So, in order to get the expected output, you need to execute

Collections.reverse (stackToList);

This will reverse the list inline and give you 3, 2, 1

Answer 3

The above answer is not right, as the order will be reverse.
Instead you can just iterate like this:

Stack<State> stack = new Stack<>();
List<State> list = new ArrayList<>();
while(!stack.isEmpty()) { 
    list.add(stack.pop()); 
}