Hibernate示例程序中的java.lang.NullPointerException

Question

我尝试运行hibernate的示例应用程序，它在运行时给出了一个错误：

  

log4j：WARN找不到logger（org.hibernate.cfg.Environment）的appender。
  log4j：WARN请正确初始化log4j系统   线程“main”java.lang.NullPointerException中的异常       at transaction.rollback（）;

这是在Main.java中：

public class Main {

public static void main(String[] args) {
    Session session = HibernateUtil.getSessionFactory().openSession();
    Transaction transaction = null;
    try {
        transaction = session.beginTransaction();
        Address address = new Address("ABC", "Delhi", "TN", "110001");
        Student student = new Student("kumar", address);
        session.save(student);
        transaction.commit();
    } catch (HibernateException e) {
        transaction.rollback();
        e.printStackTrace();
    } finally {
        session.close();
    }

Answer 1