package test2; import java.util.concurrent.CopyOnWriteArrayList; //測試GUC安全類型的集合 public class TestGUC { public static void main(String[] args) { CopyOnWriteArrayList<String> list=new CopyOnWriteArrayList<String>();//這個類原本就是安全的 for (int i = 0; i < 1000; i++) { new Thread(()->{ list.add(Thread.currentThread().getName()); }).start(); } try { Thread.sleep(3000); } catch (InterruptedException e) { e.printStackTrace(); } System.out.println(list.size()); } }