在hibernate 3.6.10 Final中使用会话工厂的空指针异常

Question

Hibernate核心xml + java

这里我尝试构建会话工厂对象，但获取NullPointerException。

HibernateUtil.java

import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

public class HibernateUtil {

    private static SessionFactory sessionFactory;

    public static void initialize() {
        try {
            Configuration config = new Configuration().configure(HibernateUtil.class.getResource("/hibernate.cfg.xml"));
            sessionFactory = config.buildSessionFactory();
        } catch (Throwable ex) {
            System.err.println("Error creating SessionFactory :" + ex);
            throw new ExceptionInInitializerError(ex);
        }
    }

    public static SessionFactory getSessionFactory() {
        return sessionFactory;
    }

    public static void shutdown() {
        sessionFactory.close();
    }

}

的hibernate.cfg.xml

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>
        <property name="hibernate.dialect">org.hibernate.dialect.PostgreSQLDialect</property>
        <property name="hibernate.connection.driver_class">org.postgresql.Driver</property>
        <property name="hibernate.connection.username">postgres</property>
        <property name="hibernate.connection.password">postgres</property>
        <property name="hibernate.connection.url">jdbc:postgresql://localhost:5432/protocol</property>
        <property name="show_sql">true</property>

        <mapping resource="in/nic/taphc/hc/protocol/persistence/State.hbm.xml"></mapping>

    </session-factory>
</hibernate-configuration>

有任何配置错误吗？请帮我弄清楚这个。