log4j

[haj1st]

hi every body ,
i am working with myeclipse ,
and i'm working on hibernate ,
as you know my eclipse automaticaly connects to data base,
i connected it and when using session and putting data in data base,
i get this log4j error,
what is this exactly?!?
and also i wanted to know about reverse engineering....

[Petr]

Hi, Can you show stack trace exceptions?

[haj1st]

here :
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" org.hibernate.MappingException: Unknown entity: sql.test.Message
at org.hibernate.impl.SessionFactoryImpl.getEntityPer sister(SessionFactoryImpl.java:628)
at org.hibernate.impl.SessionImpl.getEntityPersister( SessionImpl.java:1366)
at org.hibernate.event.def.AbstractSaveEventListener. saveWithGeneratedId(AbstractSaveEventListener.java :121)
at org.hibernate.event.def.DefaultSaveOrUpdateEventLi stener.saveWithGeneratedOrRequestedId(DefaultSaveO rUpdateEventListener.java:210)
at org.hibernate.event.def.DefaultSaveEventListener.s aveWithGeneratedOrRequestedId(DefaultSaveEventList ener.java:56)
at org.hibernate.event.def.DefaultSaveOrUpdateEventLi stener.entityIsTransient(DefaultSaveOrUpdateEventL istener.java:195)
at org.hibernate.event.def.DefaultSaveEventListener.p erformSaveOrUpdate(DefaultSaveEventListener.java:5 0)
at org.hibernate.event.def.DefaultSaveOrUpdateEventLi stener.onSaveOrUpdate(DefaultSaveOrUpdateEventList ener.java:93)
at org.hibernate.impl.SessionImpl.fireSave(SessionImp l.java:563)
at org.hibernate.impl.SessionImpl.save(SessionImpl.ja va:551)
at org.hibernate.impl.SessionImpl.save(SessionImpl.ja va:547)
at sql.test.Main.main(Main.java:16)

[Petr]

You have mistake in mapping in model hibernate.
Do you use xml or annotation? Can you show your code?

[haj1st]

i thought my eclipse does the mapping automaticaly,
doesnt it?
i'm new to hibernate and i dont know exactly how does it connect , i just want to use it and i want a quick way to connect it,can you help me?!

[Petr]

You can read about Hibernate here Hibernate Tutorial,Hibernate 3 Tutorials,Java Hibernate Example,Hibernate Online Code
I can't help you if I not see your code.
Can you show your code?