Class HashMap<T1, T2>

// 创建HashMap对象
HashMap<K, V> map = new HashMap<K, V>();

// 添加键值对
map.put(key, value);

// 获取键对应的值
V value = map.get(key);

// 移除键值对
map.remove(key);

// 判断是否包含某个键
boolean containsKey = map.containsKey(key);

// 判断是否包含某个值
boolean containsValue = map.containsValue(value);

获取HashMap中键值对的数量
int size = map.size();

// 替换value，返回旧value
V value = map.replace(key,value);

// 清空HashMap
map.clear();

// 遍历所有的键
for (K key : map.keySet()) {
    System.out.println(key);
}

// 遍历所有的值
for (V value : map.values()) {
    System.out.println(value);
}

// 遍历所有的键值对
for (Map.Entry<K, V> entry : map.entrySet()) {
    K key = entry.getKey();
    V value = entry.getValue();
    System.out.println(key + ":" + value);
}

Class Stack

Stack<Integer> stack = new Stack<>();  
public void push(E e);  
public E pop();  
public int size();  
public E peek();
public boolean empty();

Class PriorityQueue

PriorityQueue(Comparator<? super E> comparator);
public boolean offer(E e);
public E peek();
public E poll();

Interface Queue

boolean offer(E e);
E poll();
E peek();

Class ArrayDeque

boolean offerFirst(E e);
boolean	offerLast(E e);
E	pollFirst();
E	pollLast();
E	peekFirst()
E	peekLast()
int	size();
boolean	isEmpty();