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Spring + Hibernate: configuring PK generator?

We use Spring + Hibernate for a Webapp.
This Webapp will be deployed on two unrelated production sites. These two production sites will use the Webapp to generate and use Person data in parallel.
What I need to do, is to make sure that the Persons generated on these two unrelated production sites all have distinct PKs, so that we can merge the Person data from these two sites at any time.
A further constraint imposed to me is that these PKs fit in a Long, so I can't use UUIDs.
What I'm trying to do is to change the current hibernate mapping, that has sequence S_PERSON as generator:
<hibernate-mapping default-cascade="save-update" auto-import="false">
<class name="com.some.domain.Person" abstract="true">
<id name="id">
<column name="PERSON_ID"/>
<generator class="sequence">
<param name="sequence">S_PERSON</param>
</generator>
</id>
...
</hibernate-mapping>
into something configurable, so that PERSON_ID have its PKs generated from different sequences (maybe S_PERSON_1 and S_PERSON_2) depending on the deployment site's Spring configuration files.
Of course,
<generator class="sequence">
<param name="sequence">${sequenceName}</param>
</generator>
doesn't work, so I have to figure out something else... I guess my generator should point to a configurable bean that in turn points to a sequence or another, but I can't figure how to do that...
Any ideas or workaround?

You could use sequences on both production systems, but define them differently:
Production System 1:
CREATE SEQUENCE sequence_name START WITH 1 INCREMENT BY 2;
Production System 2:
CREATE SEQUENCE sequence_name START WITH 2 INCREMENT BY 2;
The first sequence will generate only odd numbers, the second only even numbers.

Hibernate: How configure entity to be inserted/updated/deleted through Oracle package procedures?

Is it possible (and if yes, how?) to map entity class to be fetched from table, but inserted/updated/deleted through procedures, instead of doing INSERT/UPDATE/DELETE on this table?
Entity configuration is done via XML, and using classes/methods specific to Oracle is OK.

You can map custom SQL for create/update/delete operations since version 3.5.
If you want to map through regular SQL statements, you can just write SQL normally inside the <sql-insert>, <sql-update>, <sql-delete> elements.
When using stored procedures, you need to mark them as callable statements and use the call syntax. Note the required out parameters for delete and update, returning the amount of rows removed.
<class name="Person">
<id name="id">
<generator class="increment"/>
</id>
<property name="name" not-null="true"/>
<sql-insert callable="true">{call createPerson (?, ?)}</sql-insert>
<sql-delete callable="true">{? = call deletePerson (?)}</sql-delete>
<sql-update callable="true">{? = call updatePerson (?, ?)}</sql-update>
</class>

Migrating Hibernate 3 to 5: relation hibernate_sequence does not exist

I am migrating an application running with Hibernate 3 to Hibernate 5.
I have a strange error:
ERROR: relation hibernate_sequence does not exist
We are using *.hbm.xml mapping files and everything was working fine until I changed the Hibernate version. I mean we have a pretty straight forward mapping with ID column and DB sequence generator and still Hibernate wasn't able to pick the correct config.
<hibernate-mapping>
<class name="com.boyan.MyClass" table="my_class">
<id name="id" type="long">
<column name="id" />
<generator class="sequence">
<param name="sequence">my_class_seq</param>
</generator>
</id>
...
</class>
</hibernate-mapping>

I started digging in the Hibernate code and saw that SequenceGenerator is deprecated and the new versions use SequenceStyleGenerator. I was very confused when I noticed that in the new version the property telling which is the sequence name is changed from sequence to sequence_name. So finally when I changed:
<param name="sequence">my_class_seq</param>
to:
<param name="sequence_name">my_class_seq</param>
everything worked.

I bumped in to the same problem and I was using annotations. Solution was the accepted answer JPA GenerationType.AUTO not considering column with auto increment. If using annotations following should be used.
#GenericGenerator(name = "my_seq", strategy = "native", parameters = {
#Parameter(name = "sequence_name", value = "mydb_seq")
})

How to prevent Hibernate from using 0 as ID?

I am using
#TableGenerator(name="tab",initialValue=2,allocationSize=50)
on Entities and define the ID with
#Id
#GeneratedValue(generator="tab",strategy=GenerationType.TABLE)
private int id;
yet Hibernate still uses 0 as an ID.
I cannot use #GenericGenerator because the annotations do not come with Hibernate4 that ships with Jboss AS7.
Is there a simple solution or do I have to write a custom Generator?

Hibernate is creating ids with id 0 because you have a primitive type. Try using Integer id instead of int id. Remember primitives can't hold a null value.
If you want to generate the custom id generator, you can use a SEQUENCE in DB to generate the id if the object.
<id ....>
<generator class="sequence">
<param name="sequence">YOUR_SEQUENCE _NAME</param>
</generator>
</id>
Read the API about generator classes here.

Hibernate's generator class not really working?

Asking this question here after hours of frustration with me and my Eclipse. Hoping to find some respite here.
I'm trying to save a pojo object into MySQL database via Hibernate 3.0. Basically my requirement is: I need to assign the id for the object before save and not let Hibernate do it for me.
For this I looked up in the documentation and saw that <generator class="assigned"/> perfectly fits my bill. Consequently I updated by .hbm.xml file with the following for the id:
<id name="id" type="int">
<column name="ID" />
<generator class="assigned" />
</id>
My pojo matches .hbm.xml file to the T.
I'm setting all the parameters including the ID of my pojo and calling Hibernate's saveOrUpdate(object) method.
If it's of any help, the ID column of my database table has "auto-inc" disabled.
Unbelievably, when I look at the database table contents, a row has been inserted with Hibernate's own ID and not what I had set.
How's it possible? Is there anything else affecting the ID? Am I missing on something? What's the work around?
My hibernate.properties looks like below(if it's of any help):
hibernate.connection.driver_class =com.mysql.jdbc.Driver
hibernate.dialect =org.hibernate.dialect.MySQLDialect
hibernate.connection.url =jdbc:mysql://localhost/dbdbdbdbdb
hibernate.connection.username=root
hibernate.connection.password=password
hibernate.connection.pool_size=10
jdbc.batch_size=30
hibernate.show_sql=true
hibernate.current_session_context_class=true
hibernate.hbm2ddl.auto=validate
hibernate.cglib.use_reflection_optimizer=false
hibernate.generate_statistics=true
hibernate.cache.use_query_cache=true
hibernate.cache.region.factory_class=net.sf.ehcache.hibernate.EhCacheRegionFactory

Well, hoax alarm!. It was really an issue with Eclipse-Tomcat integration. I had to clean up Tomcat's directories and republish before the hbm files could take effect.
Tip: If you run ant within Eclipse, be sure to keep refreshing Eclipse workspace every now and then. Learning some things the hard way.

You can write your custom sequence generator class to return ids suitable to your requirement. For more details follow: http://danu-javastuff.blogspot.com/2009/01/custom-id-generator-class-for-hibernate.html