Arrays.asList()

asList

public static <T> List<T> asList(T... a)
Returns a fixed-size list backed by the specified array. (Changes to the returned list "write through" to the array.) This method acts as bridge between array-based and collection-based APIs, in combination with Collection.toArray(). The returned list is serializable and implements RandomAccess.
This method also provides a convenient way to create a fixed-size list initialized to contain several elements:

List<String> stooges = Arrays.asList("Larry", "Moe", "Curly");

Parameters:
a - the array by which the list will be backed
Returns:
a list view of the specified array

asList

public static <T> List<T> asList(T... a)
返回一个受指定数组支持的固定大小的列表。（对返回列表的更改会“直接写”到数组。）此方法同 Collection.toArray() 一起，充当了基于数组的 API 与基于 collection 的 API 之间的桥梁。返回的列表是可序列化的，并且实现了 RandomAccess。
此方法还提供了一个创建固定长度的列表的便捷方法，该列表被初始化为包含多个元素：

List<String> stooges = Arrays.asList("Larry", "Moe", "Curly");

参数：
a - 支持列表的数组。
返回：
指定数组的列表视图。

import java.util.Arrays;
import java.util.List;

public class AddingGroups {
public static void main(String[] args) {
List<Integer> list = Arrays.asList(16,17,18);
System.out.println(list);
//list.add(11); underlying array cannot be resized

}
}

import java.util.*;
public class ModifyingArraysAsList {
public static void main(String[] args) {
Random rand = new Random(47);
Integer[] ia = {1,2,3,4,5,6,7,8,9,10};
List<Integer> list1 = new ArrayList<Integer>(Arrays.asList(ia));//ArrayList(Collection <? extends E> c)
System.out.println("Before shuffing: " + list1);
Collections.shuffle(list1,rand);
System.out.println("After shuffling: " + list1);
System.out.println("array: " + Arrays.toString(ia));//打印数组

List<Integer> list2 = Arrays.asList(ia);
System.out.println("before shuffling : " + list2);
Collections.shuffle(list2,rand);
System.out.println("After shuffing : " + list2);
System.out.println("array : " + Arrays.toString(ia));
}
}
//Arrays.asList()产生的List的对象会使用底层数组作为其物理实现是很重要的，只要你执行的操作的修改这个List，并且你不想原来的数组被修改，那么你就应该在另一个容器中创建一个副本。

Before shuffing: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

After shuffling: [4, 6, 3, 1, 8, 7, 2, 5, 10, 9]

array: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

before shuffling : [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

After shuffing : [9, 1, 6, 3, 7, 2, 5, 10, 4, 8]

array : [9, 1, 6, 3, 7, 2, 5, 10, 4, 8]

import java.util.*;
public class ArrayIsNotIterable {

public static void main(String[] args) {
Integer[] ia = {1,2,3,4,5,6,7,8,9};
List<Integer> list = Arrays.asList(ia);
list.set(1, 0);
for(Integer x : ia){
System.out.print(x + "\t");
}
System.out.println();
System.out.print("list : " + list);

}

}

1 0 3 4 5 6 7 8 9

list : [1, 0, 3, 4, 5, 6, 7, 8, 9]