asListis a generic function with variable parameters, so when an array is passed in, if the array is basic type data, it will be treated as an object, which isint[]in the question. If the data is defined asInteger[], it will be expanded as multiple variable parameters whenasListis used.

Another problem is that evenInteger[]has a generic type mismatch problem withArrayListafter conversion. In Java8, you can use stream to convert it easily. In the previous Java version, you can use loop. Here is an answer on Stack Overflow

// 声明数组 int[] arr = { 1, 10, 8 }; // 输出测试数组 System.out.println("测试的数组为：" + Arrays.toString(arr)); // 通过下角标访问元素，数组的下角标是从0开始的 System.out.println("通过数组的下角标访问元素，元素的下角标从0开始，下角标为0的元素是：" + arr[0]); // 将Array 转换成 Arraylist List ss = Arrays.asList(arr); ArrayList arrayList = new ArrayList();

List cannot be automatically converted to ArrayList

It is recommended to unify the data type, int[] arr = { 1, 10, 8 }; replaced by String[] arr = { "1", "10", "8" };

// 声明数组 String[] arr = { "1", "10", "8" }; // 输出测试数组 System.out.println("测试的数组为：" + Arrays.toString(arr)); // 通过下角标访问元素，数组的下角标是从0开始的 System.out.println("通过数组的下角标访问元素，元素的下角标从0开始，下角标为0的元素是：" + arr[0]); // 将Array 转换成 Arraylist ArrayList arrayList = new ArrayList(Arrays.asList(arr));