I'm reading and following the tutorial but I'm not able to define mapping files for inheritance.
This are my classes:

public class Author
private Vector <Album> allAlbum;
private String artName;

public class Artista extends Author
private String name;
private String surname;

public class Band extends Author
private Vector<String> components;

and this is the mapping file for Author:

<hibernate-mapping default-access="field" default-lazy="false"
default-cascade="save-update">
<class name="oodb.Author" table="author">
<id column="author_id" type="long">
<generator class="native"/>
</id>
<discriminator column="author_type" type="string"/>
<property name="artName"/>
<array name="allAlbum" table="album">
<key column="author_id"/>
<list-index column="sortOrder"/>
<one-to-many class="oodb.Album"/>
</array>
<subclass name="oodb.Band" extends="oodb.Author" discriminator-value="band">

<key column="author_id"/>
<array name="components" table="components">
<key column="author_id"/>
<list-index column="sortOrder"/>
<element column="component" type="string"/>
</array>

</subclass>
<subclass name="oodb.Artista" extends="oodb.Author" discriminator-value="solista">

<key column="author_id"/>
<property name="name" column="name"/>
<property name="surname" column="surname"/>

</subclass>

</class>
</hibernate-mapping>

I obtain the following error:

10:29:04,531 ERROR XMLHelper:61 - Error parsing XML: XML InputStream(31) The content of element type "subclass" must match "(meta*,tuplizer*,synchronize*,(property|many-to-one|one-to-one|component|dynamic-component|any|map|set|list|bag|idbag|array|primitive-array)*,join*,subclass*,loader?,sql-insert?,sql-update?,sql-delete?,resultset*,(query|sql-query)*)".
10:29:04,533 ERROR XMLHelper:61 - Error parsing XML: XML InputStream(40) The content of element type "subclass" must match "(meta*,tuplizer*,synchronize*,(property|many-to-one|one-to-one|component|dynamic-component|any|map|set|list|bag|idbag|array|primitive-array)*,join*,subclass*,loader?,sql-insert?,sql-update?,sql-delete?,resultset*,(query|sql-query)*)".

and I don't understand because I just follow what is written in the guide.
I'm sorry if it's a stupid question, I'm new to Hibernate and I searched on the net and tutorial, but didn't find much about this error.
If someone can help me or give me a reference for this I would be grateful.
thanks to all

What is the mean of the <key> elements in subclasses mapping? How i understand, you trying to map "table-per-class heierarchy" strategy, when all subclasses resides in one table with discriminator column. So, why you put <key> elements?

you are right. I was trying different combinations of tables and subclasses.
By the way,,,
...I was able to let it work in table per subclass mode, removing the <array> tag in the subclass.

now I need to know how I can map a Vector<String> object inside a subclass if I can't use <array>.

Any ideas?

why you use a vector? you can use a list and map it with bag

Ok, i tryed to use List<String> and bag but.... It gives the same error with bag!
My mapping file is:

<hibernate-mapping default-access="field" default-lazy="false"
default-cascade="save-update">
<class name="oodb.Author" table="author">
<id column="author_id" type="long">
<generator class="native"/>
</id>
<discriminator column="author_type" type="string"/>
<property name="artName"/>
<array name="allAlbum" table="album">
<key column="author"/>
<list-index />
<one-to-many class="oodb.Album"/>
</array>

<subclass name="oodb.Band" extends="oodb.Author" discriminator-value="band">
<join table="band">
<key column="band_id"/>
<property name="components" type="class"/>
<bag name="components" table="components">
<key column="comp_id" />
<element column="comp" type="string"/>
</bag>
</join>
</subclass>

<subclass name="oodb.Artista" extends="oodb.Author" discriminator-value="solista">
<join table="solista">
<key column="artist_id"/>
<property name="name" column="name"/>
<property name="surname" column="surname"/>
</join>
</subclass>

</class>
</hibernate-mapping>

and the error:

16:35:48,663 ERROR XMLHelper:61 - Error parsing XML: XML InputStream(36) The content of element type "join" must match "(subselect?,comment?,key,(property|many-to-one|component|dynamic-component|any)*,sql-insert?,sql-update?,sql-delete?)".

it doesn't want tags different from "property","many-to-one","component" inside the <join> tag.
But I don't know how to map a List<String> or Vector<String> object related to a subclass.
what is wrong?

it is right, but i think 3 table for same class hierarchy is not good thing.

from hibernate doc, about join:

"This feature is often only useful for legacy data models, we recommend fewer tables than classes and a fine-grained domain model. However, it is useful for switching between inheritance mapping strategies in a single hierarchy, as explained later."

so it's better you create one table , for class artist and his subclasses.