Add the chapter of stack and queue.

codes/java/chapter_stack_and_queue/queue.java

@@ -0,0 +1,33 @@
+package chapter_stack_and_queue;
+
+import java.util.*;
+
+public class queue {
+    public static void main(String[] args) {
+        /* 初始化队列 */
+        Queue<Integer> queue = new LinkedList<>();
+
+        /* 元素入队 */
+        queue.offer(1);
+        queue.offer(3);
+        queue.offer(2);
+        queue.offer(5);
+        queue.offer(4);
+        System.out.println("队列 queue = " + queue);
+
+        /* 访问队首元素 */
+        int peek = queue.peek();
+        System.out.println("队首元素 peek = " + peek);
+
+        /* 元素出队 */
+        int poll = queue.poll();
+        System.out.println("出队元素 poll = " + poll + "，出队后 queue = " + queue);
+
+        /* 获取队列的长度 */
+        int size = queue.size();
+        System.out.println("队列长度 size = " + size);
+
+        /* 判断队列是否为空 */
+        boolean isEmpty = queue.isEmpty();
+    }
+}