List collection initialization

Arrays tools

//The generated list is immutable
List list = Arrays.asList("1", "2", "3");
System.out.println(list);
Output
: [1, 2, 3]

// To variable required by ArrayList-packaged
List Numbers = new new
ArrayList <> (Arrays.asList ( ". 1", "2", ". 3"));
. Numbers the Add ( ". 4");
the System.out. println(numbers);
output
: [1, 2, 3, 4]

Java8 Stream

List list = Stream.of(“1”, “2”, “3”).collect(Collectors.toList());
System.out.println(list);
输出
: [1, 2, 3]