I have an entity that has a java.util.UUID class as its primary key. The key is stored in the DB as an auto-generated uniqueidentfier.

How do I annotate this? Is this even possible to do?

/**
* Example entity
*/
import java.util.UUID
import javax.persistence.*;

/**
* Address class.
*/
@Entity
@Table(name = "T_ADDRESSES")
public class Address implements java.io.Serializable {

private UUID _uuid = null;
private String _streetAddress1 = null;

/**
* Common Constructor.
*/
public Address() {}

public void setUUID(UUID uuid) {
_uuid = uuid;
}

@Id // ??
@GeneratedValue //??
@Column(name = "ADDRESS_ID")
public UUID getUUID() {
return _uuid;
}

public void setStreetAddress1(String streetAddress1) {
_streetAddress1 = streetAddress1;
}

@Column(name="STREET_ADDRESS_1")
public String getStreetAddress1() {
return _streetAddress1;
}
}

there is a Hibernate uuid generator. You can use this generator using the annotation @GenericGenerator(name="...", strategy = "uuid"). See the Hibernate Annotations reference, section 2.4.2.

I have annotated my id with the following but still receive errors

@Id
@GeneratedValue(generator="system-uuid")
@GenericGenerator(name="system-uuid", strategy = "uuid")
@Column(name="ADDRESS_ID")
public UUID getId() {
return _id;
}

From the following de-bugging output am I to expect that the SerializableType cannot process the column ADDRESS_ID (which is of type uniqueidentifier)? Or is it that a java.util.UUID cannot be constructed?

DEBUG: Mar 23, 2006 15:54:01 SessionImpl: SQL query: SELECT * FROM T_ADDRESSES
DEBUG: Mar 23, 2006 15:54:01 AbstractBatcher: about to open PreparedStatement (open PreparedStatements: 0, globally: 0)
DEBUG: Mar 23, 2006 15:54:01 ConnectionManager: opening JDBC connection
DEBUG: Mar 23, 2006 15:54:01 AbstractBatcher: preparing statement
DEBUG: Mar 23, 2006 15:54:01 AbstractBatcher: about to open ResultSet (open ResultSets: 0, globally: 0)
DEBUG: Mar 23, 2006 15:54:01 Loader: processing result set
DEBUG: Mar 23, 2006 15:54:01 Loader: result set row: 0
DEBUG: Mar 23, 2006 15:54:01 SerializationHelper: Starting deserialization of object
INFO : Mar 23, 2006 15:54:01 SerializableType: could not read column value from result set: ADDRESS_ID
DEBUG: Mar 23, 2006 15:54:01 AbstractBatcher: about to close ResultSet (open ResultSets: 1, globally: 1)
DEBUG: Mar 23, 2006 15:54:01 AbstractBatcher: about to close PreparedStatement (open PreparedStatements: 1, globally: 1)
DEBUG: Mar 23, 2006 15:54:01 AbstractBatcher: closing statement

I could probably use a more concrete example than what is in the documentation.

either map it as a String
or write a user type paiing UUID to your underlying DB type and use @Type