Java ArrayDeque

ArrayDeque<Integer> q = new ArrayDeque<>();

IntStream.range(0, 5).forEach((i) -> {q.addFirst(i);});
System.out.println(q);

IntStream.range(0, 5).forEach((i) -> {
            System.out.printf("%d, ", q.pollFirst());
        }        );

System.out.println(q);

        ArrayDeque<Integer> q = new ArrayDeque<>();

        IntStream.range(0, 5).forEach((i) -> { q.addFirst(i);  });

        System.out.println(q);

//[4, 3, 2, 1, 0]

        IntStream.range(0, 5).forEach((i) ->{System.out.printf("%d,",q.pollFirst());});

//4, 3, 2, 1, 0, 

        System.out.println(q); //[]

        //q.clear();

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