public static void main(String[] args) { Connection con = null; Statement st = null; ResultSet rs = null; String url = "jdbc:mysql://localhost:3306/testdb"; if (rs != null) { rs.close(); } if (st != null) { st.close(); } if (con != null) { displayed in the terminal. try { if (rs != null) { rs.close(); } if (st != null) { st.close(); } if (con != null) { con.close(); } ... Inside the

File: space_complexity.java === /* 指数阶（建立满二叉树） */ TreeNode buildTree(int n) { if (n == 0) return null; TreeNode root = new TreeNode(0); root.left = buildTree(n - 1); root.right = buildTree(n - 1); 过指针连接。由于结点中记录了连接关系，因此链表的存储方式相比于数组更加灵活，系统不必保证内存地址 的连续性。 链表的「结点 Node」包含两项数据，一是结点「值 Value」，二是指向下一结点的「指针 Pointer」（或称「引 用 Reference」）。 Figure 4‑5. 链表定义与存储方式 /* 链表结点类 */ class ListNode { int val; // 结点值 ListNode // 构造函数 } 尾结点指向什么？我们一般将链表的最后一个结点称为「尾结点」，其指向的是「空」，在 Java / C++ / Python 中分别记为 null / nullptr / None 。在不引起歧义下，本书都使用 null 来表示空。 4. 数组与链表 hello‑algo.com 51 链表初始化方法。建立链表分为两步，第一步是初始化各个结点对象，第二步是构建引用指向关系。完成后，

File: space_complexity.java === /* 指数阶（建立满二叉树） */ TreeNode buildTree(int n) { if (n == 0) return null; TreeNode root = new TreeNode(0); root.left = buildTree(n - 1); root.right = buildTree(n - 1); 过指针连接。由于结点中记录了连接关系，因此链表的存储方式相比于数组更加灵活，系统不必保证内存地址 的连续性。 链表的「结点 Node」包含两项数据，一是结点「值 Value」，二是指向下一结点的「指针 Pointer」（或称「引 用 Reference」）。 Figure 4‑5. 链表定义与存储方式 /* 链表结点类 */ class ListNode { int val; // 结点值 ListNode // 构造函数 } 尾结点指向什么？我们一般将链表的最后一个结点称为「尾结点」，其指向的是「空」，在 Java / C++ / Python 中分别记为 null / nullptr / None 。在不引起歧义下，本书都使用 null 来表示空。 4. 数组与链表 hello‑algo.com 51 链表初始化方法。建立链表分为两步，第一步是初始化各个结点对象，第二步是构建引用指向关系。完成后，

offered by web applications is to navigate through pages using links. In HTML a link is basically a pointer to another resource that most of the time is another page. Wicket implements links with component • getAttribute(String name): returns the value of the attribute identified by the given name, or null if the name does not correspond to any attribute. • removeAttribute(String name): removes the attribute it’s identified by an unique id which can be read calling the getId() method. This value will be null if the session is temporary. Although Wicket is able to automatically recognize when it needs to

offered by web applications is to navigate through pages using links. In HTML a link is basically a pointer to another resource that most of the time is another page. Wicket implements links with component getAttribute(String name): returns the value of the attribute identified by the given name, or 56 null if the name does not correspond to any attribute. • removeAttribute(String name): removes the attribute it’s identified by an unique id which can be read calling the getId() method. This value will be null if the session is temporary. Although Wicket is able to automatically recognize when it needs to

offered by web applications is to navigate through pages using links. In HTML a link is basically a pointer to another resource that most of the time is another page. Wicket implements links with component • getAttribute(String name): returns the value of the attribute identified by the given name, or null if the name does not correspond to any attribute. • removeAttribute(String name): removes the attribute it’s identified by an unique id which can be read calling the getId() method. This value will be null if the session is temporary. Although Wicket is able to automatically recognize when it needs to

offered by web applications is to navigate through pages using links. In HTML a link is basically a pointer to another resource that most of the time is another page. Wicket implements links with component • getAttribute(String name): returns the value of the attribute identified by the given name, or null if the name does not correspond to any attribute. • removeAttribute(String name): removes the attribute it’s identified by an unique id which can be read calling the getId() method. This value will be null if the session is temporary. Although Wicket is able to automatically recognize when it needs to

root 3.3.3.2. The null element The null element is used to handle null values. Spring treats empty arguments for properties and the like as empty code: exampleBean.setEmail(""). The special <null> element may be used to indicate a null value, so that: <null/> is equivalent to the the java code: exampleBean.setEmail(null). 3.3.3.3. The collection elements The list, set, map, and props elements allow properties and arguments of Java type List, Set, Map, and Properties, respectively

=== /* 指数阶（建立满二叉树） */ 2. 复杂度 hello‑algo.com 34 TreeNode buildTree(int n) { if (n == 0) return null; TreeNode root = new TreeNode(0); root.left = buildTree(n - 1); root.right = buildTree(n - 1); 记录了下个节点的内存地址，因此无需保证内存地址的 连续性，从而可以将各个节点分散存储在内存各处。 链表「节点 Node」包含两项数据，一是节点「值 Value」，二是指向下一节点的「指针 Pointer」，或称「引 用 Reference」。 Figure 4‑5. 链表定义与存储方式 /* 链表节点类 */ class ListNode { int val; // 节点值 ListNode x) { val = x; } // 构造函数 } � 尾节点指向什么？ 我们将链表的最后一个节点称为「尾节点」，其指向的是“空”，在 Java, C++, Python 中分别 记为 null , nullptr , None 。在不引起歧义的前提下，本书都使用 None 来表示空。 4. 数组与链表 hello‑algo.com 56 � 如何称呼链表？ 在编程语言中，数组整体就是一个变量，例如数组

root 3.3.3.2. The null element The null element is used to handle null values. Spring treats empty arguments for properties and the like as empty code: exampleBean.setEmail(""). The special <null> element may be used to indicate a null value, so that: <null/> is equivalent to the the java code: exampleBean.setEmail(null). 3.3.3.3. The collection elements Beans, BeanFactory and the ApplicationContext Spring Framework Version 1.2.6 15 The list, set, map, and props elements allow