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NullPointerException in creating Session Object using Hibernate  RSS feed

 
Agraj Mangal
Greenhorn
Posts: 1
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Hi,

I'm new to hibernate and was trying my first app with hibernate reading this tutorial: http://www.tutcity.com/view/first-hibernate.6357.html

My hibernate.cfg.xml file looks like


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My honey.hbm.xml looks like


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My Honey.java looks like



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My SessionFactoryUtil.java looks like


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Finally my stand alone java program, the client that tests this application "TestExample.java" looks like


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The exception stack trace looks like

Exception in thread "main" java.lang.NullPointerException
at com.mysql.jdbc.PreparedStatement.asSql(PreparedStatement.java:578)
at com.mysql.jdbc.PreparedStatement.asSql(PreparedStatement.java:516)
at com.mysql.jdbc.PreparedStatement.toString(PreparedStatement.java:3758)
at java.lang.String.valueOf(Unknown Source)
at java.lang.StringBuffer.append(Unknown Source)
at com.mysql.jdbc.trace.Tracer.printParameters(Tracer.aj:240)
at com.mysql.jdbc.trace.Tracer.printEntering(Tracer.aj:167)
at com.mysql.jdbc.trace.Tracer.entry(Tracer.aj:126)
at com.mysql.jdbc.trace.Tracer.ajc$before$com_mysql_jdbc_trace_Tracer$1$f51c62b8(Tracer.aj:45)
at com.mysql.jdbc.Connection.registerStatement(Connection.java)
at com.mysql.jdbc.Statement.<init>(Statement.java:267)
at com.mysql.jdbc.PreparedStatement.<init>(PreparedStatement.java:435)
at com.mysql.jdbc.ServerPreparedStatement.asSql(ServerPreparedStatement.java:360)
at com.mysql.jdbc.PreparedStatement.asSql(PreparedStatement.java:516)
at com.mysql.jdbc.ServerPreparedStatement.toString(ServerPreparedStatement.java:2433)
at java.lang.String.valueOf(Unknown Source)
at java.lang.StringBuffer.append(Unknown Source)
at com.mysql.jdbc.trace.Tracer.printParameters(Tracer.aj:240)
at com.mysql.jdbc.trace.Tracer.printEntering(Tracer.aj:167)
at com.mysql.jdbc.trace.Tracer.entry(Tracer.aj:126)
at com.mysql.jdbc.trace.Tracer.ajc$before$com_mysql_jdbc_trace_Tracer$1$f51c62b8(Tracer.aj:45)
at com.mysql.jdbc.Connection.registerStatement(Connection.java)
at com.mysql.jdbc.Statement.<init>(Statement.java:267)
at com.mysql.jdbc.PreparedStatement.<init>(PreparedStatement.java:417)
at com.mysql.jdbc.ServerPreparedStatement.<init>(ServerPreparedStatement.java:290)
at com.mysql.jdbc.Connection.prepareStatement(Connection.java:4656)
at com.mysql.jdbc.Connection.prepareStatement(Connection.java:4573)
at org.hibernate.jdbc.AbstractBatcher.getPreparedStatement(AbstractBatcher.java:534)
at org.hibernate.jdbc.AbstractBatcher.prepareSelectStatement(AbstractBatcher.java:145)
at org.hibernate.id.IncrementGenerator.getNext(IncrementGenerator.java:107)
at org.hibernate.id.IncrementGenerator.generate(IncrementGenerator.java:68)
at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:122)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:210)
at org.hibernate.event.def.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:56)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:195)
at org.hibernate.event.def.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:50)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:93)
at org.hibernate.impl.SessionImpl.fireSave(SessionImpl.java:562)
at org.hibernate.impl.SessionImpl.save(SessionImpl.java:550)
at org.hibernate.impl.SessionImpl.save(SessionImpl.java:546)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.hibernate.context.ThreadLocalSessionContext$TransactionProtectionWrapper.invoke(ThreadLocalSessionContext.java:342)
at $Proxy0.save(Unknown Source)
at com.TestExample.createHoney(TestExample.java:118)
at com.TestExample.main(TestExample.java:19)

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I'm sorry to have written all my code since i do not know because of which settings the error is coming.
I read a similar problem post on this forum : http://www.coderanch.com/t/216619/Object-Relational-Mapping/java/HI-got-null-pointer-exception
but the solution mentioned there did not helped me.

Is there a problem in hibernate.cfg.xml file ?
Why is my session null ??
because as far as i can understand it is throwing NullPointerException when i try and call any function on session object
like it is giving error in
session.save(honey)
in
createHoney(honey) method

Please help and reply what could be the problem

Best Regards,
Agraj
 
It is sorta covered in the JavaRanch Style Guide.
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