容器内部已实现锁定的并发容器
import java.util.concurrent.CopyOnWriteArrayList;
CopyOnWriteArrayList<String> list=new CopyOnWriteArrayList<String>();

public class tt {public static void main(String[]args){ CopyOnWriteArrayList<String> list=new CopyOnWriteArrayList<String>(); for(int i=0;i<99;i++) { new Thread(()-> { list.add(Thread.currentThread().getName()); //不需要再添加synchronized块 } ).start(); };}}