Convert from Queue to ArrayList [duplicate]

Answer 1

ArrayList list = new ArrayList(outputQueue);

Answer 2

Do like this

List list = new ArrayList(outputQueue);

Answer 3

Code like this

Queue outputQueue = new LinkedList();
outputQueue.add("1");
outputQueue.add("9");
outputQueue.add("3");
outputQueue.add("/");
outputQueue.add("4");
outputQueue.add("3");
outputQueue.add("-");
outputQueue.add("2");
outputQueue.add("*");
outputQueue.add("+");
ArrayList arraylist = new ArrayList(outputQueue);

Answer 4

While the other answers are the correct way to create an ArrayList. You could simply cast it to a List. This would leave the same underlying data structure (LinkedList) but you can use it as a List then.

Queue outputQueue = new LinkedList();
List list = (List)outputQueue;

Weather or not this is a better way to do what you need depends on how you are using the List. You have to decide if the cost of create a new ArrayList is worth the the potential speed increase in accessing your data. Take a look at When to use LinkedList<> over ArrayList<>?.