Java Collection - 如何添加到多线程的同步列表

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.List;

public class Main {
  public static void main(String[] args) throws InterruptedException {
     runTest();
  }
  private static void runTest() throws InterruptedException {
    Collection<String> syncList = Collections
        .synchronizedList(new ArrayList<String>(1));
    List<String> list = Arrays.asList("A", "B", "C", "D");
    List<Thread> threads = new ArrayList<Thread>();
    for (final String s : list) {
      Thread thread = new Thread(new Runnable() {
        @Override
        public void run() {
          syncList.add(s);
        }
      });
      threads.add(thread);
      thread.start();
    }
    for (Thread thread : threads) {
      thread.join();
    }
    System.out.println(syncList);
  }
}