list.add(newUser2(5,"张三5")); list.add(newUser2(6,"张三6")); list.add(newUser2(7,"张三7"));for(User2 user : list) {if(user.getId() == 5){ list.remove(user); } } System.out.println(list); } 报出异常:java.util.ConcurrentModificationException,关于这个异常的原因,看了很多...