/*
            1.添加 2.刪除 3.遍歷 4.判斷
         */
        Collection col = new ArrayList();
        col.add("張三");
        col.add("李四");
        col.add("王五");
//        col.add("張三");
        System.out.println(col);
//        col.remove("張三");
//        System.out.println(col);
        for (Object o : col) {
            System.out.println(o);
        }
        System.out.println("------------------");
        Iterator it = col.iterator();
        while (it.hasNext()){
            String next = (String) it.next();
            System.out.println(next);
        }
        System.out.println(col.isEmpty());
        System.out.println(col.contains("張三"));

 List list = new ArrayList();
        list.add("java");
        list.add("c++");
        list.add(1,"python");
        list.add(".net");
        System.out.println(list.size());
        System.out.println(list.toString());
        //1.for each遍歷
        System.out.println("---------------");
        for (Object o : list) {
            System.out.println(o);
        }
        //2.迭代器遍歷
        System.out.println("---------------");
        Iterator iterator = list.iterator();
        while (iterator.hasNext()){
            System.out.println(iterator.next());
        }
        //3.list迭代器遍歷
        System.out.println("--------正序-------");
        ListIterator listIterator = list.listIterator();
        while (listIterator.hasNext()){
            System.out.println(listIterator.next());
        }
        //逆序前必須先進行正序遍歷，讓指針指向列表最后一個元素，才能開發(fā)遍歷
        System.out.println("--------逆序-------");
        while (listIterator.hasPrevious()){
            System.out.println(listIterator.previousIndex() + ":" +listIterator.previous());
        }

public boolean add(E e) {
        ensureCapacityInternal(size + 1);  // Increments modCount!!增長修改個數
        elementData[size++] = e;
        return true;
    }
​private void ensureCapacityInternal(int minCapacity) {
        if (elementData == DEFAULTCAPACITY_EMPTY_ELEMENTDATA) {
            minCapacity = Math.max(DEFAULT_CAPACITY, minCapacity);
        }
​        ensureExplicitCapacity(minCapacity);
    }
​private void ensureExplicitCapacity(int minCapacity) {
        modCount++;
​
        // overflow-conscious code
        if (minCapacity - elementData.length > 0)
            grow(minCapacity);
    }
​private void grow(int minCapacity) {
        // overflow-conscious code
        int oldCapacity = elementData.length;
        int newCapacity = oldCapacity + (oldCapacity >> 1);
        if (newCapacity - minCapacity < 0)
            newCapacity = minCapacity;
        if (newCapacity - MAX_ARRAY_SIZE > 0)
            newCapacity = hugeCapacity(minCapacity);
        // minCapacity is usually close to size, so this is a win:
        elementData = Arrays.copyOf(elementData, newCapacity);
    }

 ArrayList arrayList = new ArrayList();
        Student s1 = new Student("張三",18);
        Student s2 = new Student("李四",18);
        Student s3 = new Student("王五",18);
        arrayList.add(s1);
        arrayList.add(s2);
        arrayList.add(s3);
        System.out.println(arrayList.toString());
        //刪除元素（需要重寫equals方法）
        arrayList.remove(new Student("李四",18));
        System.out.println(arrayList.size());
 public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Student student = (Student) o;
        return age == student.age && Objects.equals(name, student.name);
    }

Vector vector = new Vector();
        vector.add("java");
        vector.add("python");
        vector.add(".net");
        System.out.println(vector.toString());
        //枚舉器遍歷
        Enumeration elements = vector.elements();
        while (elements.hasMoreElements()){
            System.out.println(elements.nextElement());
        }

public HashSet(){
  map = new HashMap<>();
}

 HashSet<Student> set = new HashSet<>();
        Student s1 = new Student("張三",18);
        Student s2 = new Student("李四",18);
        Student s3 = new Student("王五",18);
        set.add(s1);
        set.add(s2);
        set.add(s3);
//        set.add(new Student("李四",18));
        System.out.println(set.size());
        System.out.println(set.toString());
//        set.remove(new Student("李四",18));
//        System.out.println(set.size());
//        System.out.println(set.toString());
        for (Student student : set) {
            System.out.println(student);
        }
        System.out.println("====================");
        Iterator<Student> iterator = set.iterator();
        while (iterator.hasNext()){
            System.out.println(iterator.next());
        }
public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Student student = (Student) o;
        return age == student.age && Objects.equals(name, student.name);
    }
​public int hashCode() {
        return Objects.hash(name, age);
    }

TreeSet<String> treeSet = new TreeSet<>(new Comparator<String>() {
​        @Override
        public int compare(String o1, String o2) {
             int n1 = o1.length() - o2.length();
             int n2 = o1.compareTo(o2);
             return n1==0?n2:n1;
         }
        treeSet.add("zhangSan");
        treeSet.add("wkf");
        treeSet.add("asd");
        treeSet.add("abc");
        treeSet.add("ljCv");
        treeSet.add("liSi");
        treeSet.add("wanG");
​        System.out.println(treeSet.toString());
        System.out.println(treeSet.size());
​

Map<String, String> map = new HashMap<>();
        map.put("wkf","666");
        map.put("qwe","678");
        map.put("kfc","999");
        map.put("asd","694");
        Set<String> keySet = map.keySet();
        for (String s : keySet) {
            System.out.println(s + "=" + map.get(s));
        }
        System.out.println("===================");
        Set<Map.Entry<String, String>> entries = map.entrySet();
        for (Map.Entry<String, String> entry : entries) {
            System.out.println(entry.getKey() +"=" + entry.getValue() );
        }

static final int DEFAULT_INITIAL_CAPACITY = 1 << 4; // hashMap初始容量大小16
static final int MAXIMUM_CAPACITY = 1 << 30;//hashMap的數組最大容量
static final float DEFAULT_LOAD_FACTOR = 0.75f;//默認加載因子
static final int TREEIFY_THRESHOLD = 8;//jdk1.8開始，當鏈表長度大于8時，調整成紅黑樹
static final int UNTREEIFY_THRESHOLD = 6;//jdk1.8開始，當鏈表長度小于6時，調整成鏈表
static final int MIN_TREEIFY_CAPACITY = 64;//jdk1.8開始，當鏈表長度大于8時，并且集合元素個數大于等于64時調整成紅黑樹
transient Node<K,V>[] table;//哈希表中的數組