Hi,
I get the follwoing different types of errors "intermittently" with Hibernate version 3,mysql 3.23 on linux fedora 2.

1.org.hibernate.exception.GenericJDBCException: could not load an entity: [com.harmot.school.University#stanford]
at org.hibernate.exception.ErrorCodeConverter.handledNonSpecificException(ErrorCodeConverter.java:92)
at org.hibernate.exception.ErrorCodeConverter.convert(ErrorCodeConverter.java:80)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
at org.hibernate.loader.Loader.loadEntity(Loader.java:1359)
at org.hibernate.loader.entity.EntityLoader.load(EntityLoader.java:116)
etc.

2.Caused by: java.sql.SQLException: You can't operate on a closed connection!!!
at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:68)
at com.mchange.v2.c3p0.impl.NewProxyConnection.prepareStatement(NewProxyConnection.java:198)
at org.hibernate.jdbc.AbstractBatcher.getPreparedStatement(AbstractBatcher.java:396)
at org.hibernate.jdbc.AbstractBatcher.getPreparedStatement(AbstractBatcher.java:334)
at org.hibernate.jdbc.AbstractBatcher.prepareQueryStatement(AbstractBatcher.java:88)
at org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1162)
at org.hibernate.loader.Loader.doQuery(Loader.java:390)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:218)
at org.hibernate.loader.Loader.loadEntity(Loader.java:1345)
... 47 more
Caused by: java.lang.NullPointerException
at com.mchange.v2.c3p0.impl.NewProxyConnection.prepareStatement(NewProxyConnection.java:173)
... 54 more


3. Caused by: com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:

** BEGIN NESTED EXCEPTION **

java.io.EOFException

STACKTRACE:

java.io.EOFException
at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:1902)
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2348)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2858)
...** END NESTED EXCEPTION **



Last packet sent to the server was 1 ms ago.
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2560)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2858)



Interestingly ,the app was working fine earlier.We split the database into 2 with different cfg files and seperate sessionFactory objects. But that does not seem to be a logical cause.
Any help would be highly appreciated.

Thanks
Ajay

The cause of the error seems more like a network error between the app and database than anything else. Or the MySQL driver is a bit iffy, is it a late version?

I am using mysql-connector-java-3.1.10-bin.jar and mysql 3.23.58 .