运行时报错，这是怎么回事

2016-4-12 22:36:42 org.hibernate.annotations.common.Version <clinit>

INFO: HCANN000001: Hibernate Commons Annotations {4.0.2.Final}

2016-4-12 22:36:42 org.hibernate.Version logVersion

INFO: HHH000412: Hibernate Core {4.2.4.Final}

2016-4-12 22:36:42 org.hibernate.cfg.Environment <clinit>

INFO: HHH000206: hibernate.properties not found

2016-4-12 22:36:42 org.hibernate.cfg.Environment buildBytecodeProvider

INFO: HHH000021: Bytecode provider name : javassist

2016-4-12 22:36:42 org.hibernate.cfg.Configuration configure

INFO: HHH000043: Configuring from resource: /hibernate.cfg.xml

2016-4-12 22:36:42 org.hibernate.cfg.Configuration getConfigurationInputStream

INFO: HHH000040: Configuration resource: /hibernate.cfg.xml

2016-4-12 22:36:42 org.hibernate.internal.util.xml.DTDEntityResolver resolveEntity

WARN: HHH000223: Recognized obsolete hibernate namespace http://hibernate.sourceforge.net/. Use namespace http://www.hibernate.org/dtd/ instead. Refer to Hibernate 3.6 Migration Guide!

2016-4-12 22:36:43 org.hibernate.cfg.Configuration addResource

INFO: HHH000221: Reading mappings from resource: entity/Students.hbm.xml

请大神帮帮忙