求各位高手帮忙（hibernate）

Exception in thread "main" java.lang.NoClassDefFoundError: org/hibernate/loader/custom/SQLQueryReturn
at org.hibernate.cfg.annotations.QueryBinder.bindSqlResultsetMapping(QueryBinder.java:293)
at org.hibernate.cfg.AnnotationBinder.bindQueries(AnnotationBinder.java:238)
at org.hibernate.cfg.AnnotationBinder.bindClass(AnnotationBinder.java:403)
at org.hibernate.cfg.AnnotationConfiguration.processArtifactsOfType(AnnotationConfiguration.java:353)
at org.hibernate.cfg.AnnotationConfiguration.secondPassCompile(AnnotationConfiguration.java:265)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1319)
at com.bjsxt.hibernate.TeacherTest.main(TeacherTest.java:14)
Caused by: java.lang.ClassNotFoundException: org.hibernate.loader.custom.SQLQueryReturn
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)是一个什么样的错误？