Java怎样创建集合才能避免造成内存泄漏你了解吗

Set users = new HashSet();
users.add("Hollis");
users.add("hollis");
users.add("HollisChuang");
users.add("hollis666");
transferUsers(users);

public class DoubleBraceTest {
    public static void main(String[] args) {
        Set users = new HashSet() {{
            add("Hollis");
            add("hollis");
            add("HollisChuang");
            add("hollis666");
        }};
    }
}

Map<String,String> users = new HashMap<>() {{
    put("Hollis","Hollis");
    put("hollis","hollis");
    put("HollisChuang","HollisChuang");
}};

javac DoubleBraceTest.java

DoubleBraceTest.class
DoubleBraceTest$1.class

Map hollis = new HashMap(){{
    put("firstName", "Hollis");
    put("lastName", "Chuang");
    put("contacts", new HashMap(){{
        put("0", new HashMap(){{
            put("blogs", "http://www.hollischuang.com");
        }});
        put("1", new HashMap(){{
            put("wechat", "hollischuang");
        }});
    }});
}};

DoubleBraceTest$1$1$1.class
DoubleBraceTest$1$1$2.class
DoubleBraceTest$1$1.class
DoubleBraceTest$1.class
DoubleBraceTest.class

public Map getMap() {
    Map hollis = new HashMap(){{
        put("firstName", "Hollis");
        put("lastName", "Chuang");
        put("contacts", new HashMap(){{
            put("0", new HashMap(){{
                put("blogs", "http://www.hollischuang.com");
            }});
            put("1", new HashMap(){{
                put("wechat", "hollischuang");
            }});
        }});
    }};

    return hollis;
}

public class DoubleBraceTest {
    public static void main(String[] args) {
        DoubleBraceTest doubleBraceTest = new DoubleBraceTest();
        Map map = doubleBraceTest.getMap();
    }
}

Field field = map.getClass().getDeclaredField("this$0");
field.setAccessible(true);
System.out.println(field.get(map).getClass());

List<String> list2 = Arrays.asList("hollis ", "Hollis", "HollisChuang");

List<String> list1 = Stream.of("hollis", "Hollis", "HollisChuang").collect(Collectors.toList());

ImmutableMap.of("k1", "v1", "k2", "v2");
ImmutableList.of("a", "b", "c", "d");

/**
 * Returns an unmodifiable list containing zero elements.
 *
 * See <a href="#unmodifiable" rel="external nofollow" >Unmodifiable Lists</a> for details.
 *
 * @param <E> the {@code List}'s element type
 * @return an empty {@code List}
 *
 * @since 9
 */
static <E> List<E> of() {
    return ImmutableCollections.emptyList();
}

static <E> List<E> of(E e1) {
    return new ImmutableCollections.List12<>(e1);
}

static <E> List<E> of(E... elements) {
    switch (elements.length) { // implicit null check of elements
        case 0:
            return ImmutableCollections.emptyList();
        case 1:
            return new ImmutableCollections.List12<>(elements[0]);
        case 2:
            return new ImmutableCollections.List12<>(elements[0], elements[1]);
        default:
            return new ImmutableCollections.ListN<>(elements);
    }
}