Hi,
When we use sequence with custom name, still hibernate tries to query with hibernate_sequence default name.

Usage in hbm.xml:
<id name="contact_id" column="CONTACT_ID">
<generator class="sequence">
<param name="sequence">seq</param>
</generator>
</id>

when i try to print the stacktrace in our dialect,

java.lang.Exception: Stack trace
at java.lang.Thread.dumpStack(Thread.java:1329)
at org.hibernate.dialect.SqlmxDialect.getSequenceNextValString(SqlmxDialect.java:549)
at org.hibernate.id.enhanced.SequenceStructure.registerExportables(SequenceStructure.java:166)
at org.hibernate.id.enhanced.SequenceStyleGenerator.registerExportables(SequenceStyleGenerator.java:452)
at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.handleIdentifierValueBinding(InFlightMetadataCollectorImpl.java:2275)
at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processExportableProducers(InFlightMetadataCollectorImpl.java:2231)
at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.buildMetadataInstance(InFlightMetadataCollectorImpl.java:2194)
at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:305)
at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.build(MetadataBuildingProcess.java:83)
at org.hibernate.boot.internal.MetadataBuilderImpl.build(MetadataBuilderImpl.java:418)
at org.hibernate.boot.internal.MetadataBuilderImpl.build(MetadataBuilderImpl.java:87)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:692)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:727)
at com.mycompany.ContactManager.main(ContactManager.java:33)

it looks even if we mention custom sequence name when we use sequence as a generator it looks for default sequence name (hibernate_sequence). Kindly check.