java版本：SDK 1.8.0_151IDE：IntelliJ IDEAimport java.awt.Queue;import java.util.LinkedList;public class SimpleMovingAverage {    private final Queue<Double> window = new LinkedList<Double>();    private final int period;    private double sum;    public SimpleMovingAverage(int period) {        assert period > 0 : "Period must be a positive integer";        this.period = period;    }    public void newNum(double num) {        sum += num;        window.add(num);        if (window.size() > period) {            sum -= window.remove();        }    }    public double getAvg() {        if (window.isEmpty()) {return 0.0;} // technically the average is undefined        return sum / window.size();    }    public static void main(String[] args) {        double[] testData = {1, 2, 3, 4, 5, 5, 4, 3, 2, 1};        int[] windowSizes = {3, 5};        for (int windSize : windowSizes) {            SimpleMovingAverage ma = new SimpleMovingAverage(windSize);            for (double x : testData) {                ma.newNum(x);                System.out.println("Next number = " + x + ", SMA = " + ma.getAvg());            }            System.out.println();        }    }}上面的代碼來自https://rosettacode.org/wiki/Averages/Simple_moving_average#Java當我創建一個名為 SimpleMovingAverage 的類并從上述網站復制代碼時，會報告錯誤?！癹ava.awt.Queue”在“java.awt”中不是公開的。無法從外部包訪問怎么解決呢？