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

properly detect JDK 1.6/1.7 (Java 6/7) as higher than 1.5 (Java 5) * fixed SpringVersion to return null if the package is not determinable because of ClassLoader restrictions * fixed PathMatchingResourcePatternResolver warn logs for acceptable conditions * JdbcTemplate uses "PreparedStatement.setObject(index, null)" for null values with unknown SQL type on Informix * JdbcTemplate by default uses "PreparedStatement.setString" constract details * CharacterEncodingFilter only applies its encoding if actually specified (non- null) * WebDataBinder explicitly suppresses field marker prefix values in case of "ignoreUnknownFields"

Package org.springframework.aop * AbstractAutoProxyCreator (as used by "aop:config") correctly ignores null bean instances * "aop:aspect" doesn't insist on aspect bean reference to be specified when just SmartInstantiationAwareBeanPostProcessor's "determineCandidateConstructors" is only invoked for non-null bean Class * ServiceLocatorFactoryBean handles equals and hashCode based on proxy object identity a generic superclass method * @ModelAttribute annotated handler method arguments can resolve to a null value as well (when contained in the model) * standard method argument subtypes (such as a Principal

Package org.springframework.aop * AbstractAutoProxyCreator (as used by "aop:config") correctly ignores null bean instances * "aop:aspect" doesn't insist on aspect bean reference to be specified when just SmartInstantiationAwareBeanPostProcessor's "determineCandidateConstructors" is only invoked for non-null bean Class * ServiceLocatorFactoryBean handles equals and hashCode based on proxy object identity a generic superclass method * @ModelAttribute annotated handler method arguments can resolve to a null value as well (when contained in the model) * standard method argument subtypes (such as a Principal

"getDefaultDestination()" and "getDefaultDestinationName()" * AbstractJmsListeningContainer sets Connection to null on shutdown, allowing for smooth reinitialization * DefaultMessageListenerContainer performs lazy * AbstractAutowireCapableBeanFactory only invokes "predictBeanType" post-processor method for non-null bean Class Package org.springframework.core * introduced InfrastructureProxy interface for resource OSGi compatibility) Package org.springframework.jdbc * JdbcTemplate explicitly detects and skips null ResultSets returned from CallableStatement * BeanPropertySqlParameterSource avoids default use of

* AbstractAutowireCapableBeanFactory only invokes "predictBeanType" post-processor method for non-null bean Class Package org.springframework.core * introduced InfrastructureProxy interface for resource OSGi compatibility) Package org.springframework.jdbc * JdbcTemplate explicitly detects and skips null ResultSets returned from CallableStatement * BeanPropertySqlParameterSource avoids default use of and FrameworkServlet * RequestContext does not fail when WebApplicationContext's ServletContext is null (like in a plain Portlet environment) * fixed JSP form tags to properly return SKIP_BODY instead

bean instantiation failure * fixed BeanWrapperImpl to convert a null input for an array type to a null value rather than an array with null element * changed MutablePropertyValues's "addPropertyValue" signature remain binary compatible with Spring <=1.2.6 * fixed BeanArrayPropertyEditor to translate null value to null byte array * added CharArrayPropertyEditor to translate String value into char array * CharacterEditor defined in child Package org.springframework.core * refined NestedXxxException to properly handle null message in root cause, through using the cause's "toString()" * fixed FileSystemResource/UrlResource

Package org.springframework.beans * CharacterEditor's "allowEmpty" only translates empty String to null, keeping a single space String as space character * CustomNumberEditor treats number with leading ClassLoader explicitly excludes types to match (for OSGi LTW compatibility) * restored support for null location array argument in ClassPathXmlApplicationContext (for Apache CXF compatibility) * added ENC names by default) * NativeJdbcExtractorAdapter only processes DatabaseMetaData Connection if non-null (for WebLogic cluster compatibility) * fixed SQLException translation for IBM DB2 and MS SQL to operate

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); // 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: linked_list.java === /* 删除链表的结点 n0 之后的首个结点 */ void remove(ListNode n0) { if (n0.next == null) return; // n0 -> P -> n1 ListNode P = n0.next; ListNode n1 = P.next; n0.next = n1; } 4.2.2

"nullValue" property to PropertyPlaceholderConfigurer, allowing for resolving specific Strings into a null value * CustomEditorConfigurer and CustomScopeConfigurer accept editor/scope values as class names AbstractAutowireCapableBeanFactory to skip invocation of InstantiationAwareBeanPostProcessors for null bean * fixed AbstractAutowireCapableBeanFactory to always resolve the bean class before a FactoryBean of 'busy' waiting in case of thread interruption * JdbcTemplate falls back to type VARCHAR for a null value in case of an unknown SQL type specified against IBM DB2 * JdbcTemplate uses "PreparedStatement