Hibernate version: 2.6.1

Name and version of the database you are using: Oracle 9i

The generated SQL (show_sql=true):
Hibernate: select specialty_id_seq.nextval from dual
Hibernate: insert into PORTAL_CLINICALGUID_SPECIALTY (name, specialty_id) values (?, ?)

I am getting an ORA-00001 unique constraint (xxxx) violated.

I know this is because the sequence is starting with a value of 1.

The table in question has been prepopulated with approximately 50 rows.

Here is the XDoclet used to define the generator:

/**
* @hibernate.id
* column = "specialty_id"
* generator-class = "sequence"
* unsaved-value = "-999"
* @hibernate.generator-param
* name="sequence"
* value="specialty_id_seq"
*/


Is there a way I can set the starting sequence value to say 100?

you will need to reset the value at database level.

or exhaust some values from sequence by calling following several times.

select specialty_id_seq.nextval from dual

As you are using Sequence Generator of Oracle , you cannot configure Sequence Id in Hibernate, but you could setup your Sequence in oracle to start from 50.

Example
CREATE SEQUENCE employee_id_no START WITH 51 INCREMENT BY 1 MAXVALUE 9999;[/b]

I actually found the solution. It may break compatibility with other db's that use the "sequence" generator but here is all I had to do.

Original:
/**
* @hibernate.id
* column = "specialty_id"
* generator-class = "sequence"
* unsaved-value = "-999"
* @hibernate.generator-param
* name="sequence"
* value="specialty_id_seq"
*/

/**
* @hibernate.id
* column = "specialty_id"
* generator-class = "sequence"
* unsaved-value = "-999"
* @hibernate.generator-param
* name="sequence"
* value="specialty_id_seq"
* @hibernate.generator-param
* name="parameters"
* value="START WITH 100"
*/

Notice the addition of the second "generator-param" this allows parameters to passed directly to the DDL.