当我使用以下代码实例化Hibernate时：

        Configuration configuration = new Configuration();
        configuration.configure();
        serviceRegistry = new ServiceRegistryBuilder().applySettings(
                configuration.getProperties()).buildServiceRegistry();
        sessionFactory = configuration.buildSessionFactory(serviceRegistry);

我有以下例外情况：

org.xml.sax.SAXParseException：文档无效：找不到语法。org.xml.sax.SAXParseException：文档根元素“
hibernate-configuration”必须与DOCTYPE根“
null”匹配。引起原因：org.hibernate.MappingException：org.hibernate.cfg.Configuration.configure（Configuration.java:1931）处org.hibernate.cfg.Configuration.doConfigure（Configuration.java:2014）处的配置无效。
cfg.Configuration.configure（Configuration.java:1910）位于com.soccer.system.HibernateUtil。（HibernateUtil.java:23）…
1更多原因：org.xml.sax.SAXParseException：文档无效：无语法找到了。

我在hibernate.cfg.xmlHibernate 4.1.6中使用以下文件：

<?xml version='1.0' encoding='utf-8'?>

<hibernate-configuration
    xmlns="http://www.hibernate.org/xsd/hibernate-configuration"
    xsi:schemaLocation="http://www.hibernate.org/xsd/hibernate-configuration hibernate-configuration-4.0.xsd"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <session-factory>
        <!-- Database connection settings -->
        <property name="connection.driver_class">org.apache.derby.jdbc.ClientDriver</property>
        <property name="connection.url">jdbc:derby://localhost:1527/K:\db</property>
        <property name="connection.username"></property>
        <property name="connection.password"></property>

        <!-- JDBC connection pool (use the built-in) -->
        <property name="connection.pool_size">1</property>

        <!-- SQL dialect -->
        <property name="dialect">org.hibernate.dialect.DerbyDialect</property>

        <!-- Enable Hibernate's automatic session context management -->
        <property name="current_session_context_class">thread</property>

        <!-- Disable the second-level cache -->
        <property name="cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</property>

        <!-- Echo all executed SQL to stdout -->
        <property name="show_sql">true</property>

        <!-- Drop and re-create the database schema on startup -->
        <property name="hbm2ddl.auto">update</property>
    </session-factory>
</hibernate-configuration>

我该怎么做才能消除此异常？