4 methods of ArrayList initialization

From https://blog.csdn.net/u011523796/article/details/79537055

Arrays.asList

ArrayList obj = new ArrayList(Arrays.asList(Object o1, Object o2, Object o3, …so on));

Generate an anonymous internal internal for initialization

ArrayList obj = new ArrayList() { {
add(Object o1);
add(Object o2);
…
…
}};

Conventional way

ArrayList obj = new ArrayList();
obj.add(“o1”);
obj.add(“o2”);
…
…
或者
ArrayList obj = new ArrayList();
List list = Arrays.asList(“o1”,“o2”,…);
obj.addAll(list);

Collections.ncopies

ArrayList obj = new ArrayList(Collections.nCopies(count,element));//Copy the element count times and fill it into the ArrayList

Anonymous inner class generation map
https://www.cnblogs.com/yanggb/p/11590225.html