Utilizando @SequenceGenerator do hibernate com o Firebird

Para utilizar Sequence do firebird, basta criar o generator no banco de dados:

"CREATE SEQUENCE GEN_USUARIO_ID;"

E depois disso, utilizar este nome na entidade, mapeando da seguinte forma:

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.SequenceGenerator;
import javax.persistence.Table;

@Entity
@SequenceGenerator(name = "INC_USUARIO", sequenceName = "GEN_USUARIO_ID")
@Table(name = "usuario")
public class User {

  @Id
  @GeneratedValue(strategy = GenerationType.AUTO, generator = "INC_USUARIO")
  private Long id;

  @Column
  private String nome;

E o mapeamento do arquivo hibernate.cfg.xml fica normal.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
 <session-factory name="Hibernate" >
  <!-- Database connection settings -->
  <property name="connection.driver_class">org.firebirdsql.jdbc.FBDriver</property>
  <property name="connection.url">jdbc:firebirdsql:localhost/3050:E:\Desenv\Base\base.fdb</property>
  <property name="connection.username">sysdba</property>
  <property name="connection.password">masterkey</property>
  <!-- JDBC connection pool (use the built-in) -->
  <property name="connection.pool_size">1</property>
  <!-- SQL dialect -->
  <property name="dialect">org.hibernate.dialect.FirebirdDialect</property>
  <!-- Enable Hibernate's automatic session context management -->
  <property name="current_session_context_class">thread</property>
  <!-- Disable the second-level cache -->
  <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
  <!-- Echo all executed SQL to stdout -->
  <property name="show_sql">true</property>
  
  <!-- property name="hibernate.hbm2ddl.auto">create</property> -->

  <mapping class="br.com.viartes.entities.User" />
 </session-factory>
</hibernate-configuration>