HashSet、LinkedHashSet、TreeSet比较

Set<Integer> hashSet = new HashSet<Integer>();
Set<Integer> synchronizedSet = Collections.synchronizedSet(new HashSet<Integer>());
Set<Integer> linkedHashSet = new LinkedHashSet<Integer>();
Set<Integer> treeSet = new TreeSet<Integer>(new Comparator<Integer>() {
            public int compare(Integer a0, Integer a1) {
                if (a0 > a1) {
                    return -1;
                } else if (a0 < a1) {
                    return 1;
                } else {
                    return 0;
                }
            };
        });