ArrayList警告-警告：[unchecked]对add（E）的未经检查的调用，也不会运行文件

更改此行

private List listOfPrimeNumbers;  //add a member variable for the ArrayList

至

private List<Integer> listOfPrimeNumbers;  //add a member variable for the ArrayList

这将消除警告。

奖励 -您可能想在方法内部使用 增强的for循环

print

public void print() {  int i = 1;   for (Integer nextPrime:listOfPrimeNumbers) {      System.out.println("the " + i + "th prime is: " + nextPrime);      i++;  }}