org.hibernate.exception.GenericJDBCException: Cannot open connection
org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:91)
org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:79)
org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:29)
org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:307)
org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:109)
org.hibernate.jdbc.AbstractBatcher.prepareQueryStatement(AbstractBatcher.java:105)
org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1561)
org.hibernate.loader.Loader.doQuery(Loader.java:661)
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:223)
org.hibernate.loader.Loader.loadEntity(Loader.java:1782)
org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:93)
org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:81)
org.hibernate.persister.entity.AbstractEntityPersister.load(AbstractEntityPersister.java:2729)
org.hibernate.event.def.DefaultLoadEventListener.loadFromDatasource(DefaultLoadEventListener.java:365)
org.hibernate.event.def.DefaultLoadEventListener.doLoad(DefaultLoadEventListener.java:346)
org.hibernate.event.def.DefaultLoadEventListener.load(DefaultLoadEventListener.java:123)
org.hibernate.event.def.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:82)
org.hibernate.impl.SessionImpl.fireLoad(SessionImpl.java:812)
org.hibernate.impl.SessionImpl.immediateLoad(SessionImpl.java:772)
org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:62)
org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:98)
org.hibernate.proxy.CGLIBLazyInitializer.intercept(CGLIBLazyInitializer.java:158)
FileToSave$$EnhancerByCGLIB$$8691d1b6.getType(<generated>)
Upload.doPost(Upload.java:58)
javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.catalina.servlets.InvokerServlet.serveRequest(InvokerServlet.java:419)
org.apache.catalina.servlets.InvokerServlet.doPost(InvokerServlet.java:169)
javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

-----------------

elaborate

Testing hibernation loading...

SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
session =sessionFactory.openSession();
System.out.println("Hello2");
// This step will retrieve an instance FileToSave from the database.
// If you have the Name, you can use a Session to return it:
FileToSave saveFile =(FileToSave)session.load(FileToSave.class,"somepicture");

System.out.println(saveFile.getName());
System.out.println(saveFile.getType());
System.out.println(saveFile.getSize());
-----------

<hibernate-mapping>
<class name="FileToSave" table="filetosave">
<id name="name" column="name" type="java.lang.String"/>
<property name="type" column="type" type="java.lang.String"/>
<property name="size" column="Size" type="java.lang.Long"/>
</class>
</hibernate-mapping>

-------------
org.hibernate.exception.GenericJDBCException: Cannot open connection
org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:91)
org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:79)
org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:29)
org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:307)
org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:109)
org.hibernate.jdbc.AbstractBatcher.prepareQueryStatement(AbstractBatcher.java:105)
org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1561)
org.hibernate.loader.Loader.doQuery(Loader.java:661)
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:223)
org.hibernate.loader.Loader.loadEntity(Loader.java:1782)
org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:93)
org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:81)
org.hibernate.persister.entity.AbstractEntityPersister.load(AbstractEntityPersister.java:2729)
org.hibernate.event.def.DefaultLoadEventListener.loadFromDatasource(DefaultLoadEventListener.java:365)
org.hibernate.event.def.DefaultLoadEventListener.doLoad(DefaultLoadEventListener.java:346)
org.hibernate.event.def.DefaultLoadEventListener.load(DefaultLoadEventListener.java:123)
org.hibernate.event.def.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:82)
org.hibernate.impl.SessionImpl.fireLoad(SessionImpl.java:812)
org.hibernate.impl.SessionImpl.immediateLoad(SessionImpl.java:772)
org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:62)
org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:98)
org.hibernate.proxy.CGLIBLazyInitializer.intercept(CGLIBLazyInitializer.java:158)
FileToSave$$EnhancerByCGLIB$$d19556f0.getSize(<generated>)

Please go to the user forum; thanks.

Correction: This problem has been solved by looking into hibernate.cfg.xml file.