top k largest numbers

public class Solution {
    /**
     * @param nums: an integer array
     * @param k: An integer
     * @return: the top k largest numbers in array
     */
    public int[] topk(int[] nums, int k) {
        if (nums == null || nums.length <= 1) return nums;

        PriorityQueue<Integer> pq = new PriorityQueue<Integer>(nums.length, Collections.reverseOrder());
        for (int num : nums) {
            pq.offer(num);
        }

        int[] maxK = new int[k];
        for (int i = 0; i < k; i++) {
            maxK[i] = pq.poll();
        }

        return maxK;
    }
}