Java array.add() 停止程序

Question

我设法在我的数组中动态添加一个元素，但不幸的是程序停止了。我该如何继续？谢谢！

....

List<String> messages = Arrays.asList("Mary", "Nadia!", "Drake");

System.out.println("Enter Costumer's Name:"); 
cust_name =in.next();
if(cust_name .equals("Mary"))
System.out.println("Already a member!");
else if (cust_name .equals("Nadia"))
System.out.println("Already a member!");
else if(cust_name .equals("Drake"))
System.out.println("Already a member!");
else
messages.add(in.next());
System.out.println("Not a member! " + cust_name + " just added.");

....

Answer 1

Arrays.asList() 返回一个固定大小的List，我能想到的最简单的解决方法是-

List<String> messages = new ArrayList<String>(
    Arrays.asList("Mary", "Nadia!", "Drake")
); // Creates a new (mutable) list.

Answer 2

Arrays.asList 返回的List 是固定大小的。尝试添加会导致异常。

如果您希望将动态列表初始化为某些值，请执行以下操作：

List<String> messages = new ArrayList<String>(Arrays.asList("Mary", "Nadia!", "Drake"));

或者更好的是使用Google Guava's Lists.newArrayList

List<String> messages = Lists.newArrayList("Mary", "Nadia!", "Drake");