Generate hamming numbers in order

Hamming.java

import java.util.*;

class Hamming
{
	static List<Integer> getHamming(int n) {
		int count = 1;
		List<Integer> hams = new ArrayList<>();
		Set<Integer> seen = new HashSet<>();
		hams.add(1);
		int next = 1;

		Queue<Integer> q2 = new ArrayDeque<>();
		Queue<Integer> q3 = new ArrayDeque<>();
		Queue<Integer> q5 = new ArrayDeque<>();

		while (count < n) {
			q2.add(2 * next);
			q3.add(3 * next);
			q5.add(5 * next);

			if (q2.peek() < q3.peek()) {
				if (q2.peek() < q5.peek()) {
					next = q2.poll();
				} else {
					next = q5.poll();
				}
			} else {
				if (q3.peek() < q5.peek()) {
					next = q3.poll();
				} else {
					next = q5.poll();
				}
			}

			if (!seen.contains(next)) {
				hams.add(next);
				seen.add(next);
				++count;
			}
		}
		return hams;
	}

	public static void main(String[] args) {
		List<Integer> hams = getHamming(21);
		System.out.println(hams);
	}
}