Hibernate运行时候报java.lang.ExceptionInInitializerError异常 之前测试的时候都好好的 现在连之前的项目都不好使了

SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/C:/Users/Administrator/AppData/Local/Genuitec/MyEclipse-8.6/configuration/org.eclipse.osgi/bundles/89/1/.cp/myeclipse-data/3.3/lib/required/slf4j-log4j12-1.5.8.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/D:/Workspace/Hibernate/WebRoot/WEB-INF/lib/slf4j-log4j12-1.5.2.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
log4j:WARN No appenders could be found for logger (org.hibernate.cfg.Environment).
log4j:WARN Please initialize the log4j system properly.
Exception in thread "main" java.lang.ExceptionInInitializerError
at com.Grade.TestGrade.save(TestGrade.java:37)
at com.Grade.TestGrade.main(TestGrade.java:18)
Caused by: org.hibernate.InvalidMappingException: Could not parse mapping document from resource com/Grade/Student.hbm.xml
at org.hibernate.cfg.Configuration.addResource(Configuration.java:616)
at org.hibernate.cfg.Configuration.parseMappingElement(Configuration.java:1635)
at org.hibernate.cfg.Configuration.parseSessionFactory(Configuration.java:1603)
at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1582)
at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1556)
at org.hibernate.cfg.Configuration.configure(Configuration.java:1476)
at org.hibernate.cfg.Configuration.configure(Configuration.java:1462)
at cn.jbit.util.HibernateUtil.<clinit>(HibernateUtil.java:23)
... 2 more
Caused by: org.hibernate.DuplicateMappingException: duplicate import: Student refers to both com.Grade.Student and cn.jbit.entity.Student (try using auto-import="false")
at org.hibernate.cfg.Mappings.addImport(Mappings.java:164)
at org.hibernate.cfg.HbmBinder.bindPersistentClassCommonValues(HbmBinder.java:636)
at org.hibernate.cfg.HbmBinder.bindClass(HbmBinder.java:549)
at org.hibernate.cfg.HbmBinder.bindRootClass(HbmBinder.java:293)
at org.hibernate.cfg.HbmBinder.bindRoot(HbmBinder.java:166)
at org.hibernate.cfg.Configuration.add(Configuration.java:716)
at org.hibernate.cfg.Configuration.addInputStream(Configuration.java:551)
at org.hibernate.cfg.Configuration.addResource(Configuration.java:613)
... 9 more
Hibernate 异常

补充：企业软件 ,  Lotus