Question

I can’t get Hibernate working with java.util.UUID for PostgreSQL.

Here is the mapping using javax.persistence.* annotations:

private UUID itemUuid;

@Column(name="item_uuid",columnDefinition="uuid NOT NULL")
public UUID getItemUuid() {
    return itemUuid;
}

public void setItemUuid(UUID itemUuid) {
    this.itemUuid = itemUuid;
}

When persisting a transient object I get a SQLGrammarException:

column "item_uuid" is of type uuid but expression is of type bytea at character 149

PostgreSQL version is 8.4.4
JDBC driver – 8.4.4-702 (also tried 9.0 – same thing)
Hibernate version is 3.6, main configuration properties:

<property name="hibernate.dialect">org.hibernate.dialect.PostgreSQLDialect</property>
<property name="hibernate.connection.driver_class">org.postgresql.Driver</property>
<property name="hibernate.connection.url">jdbc:postgresql://192.168.1.1/db_test</property>

Answer 1

This can be solved by adding the following annotation to the UUID:

import org.hibernate.annotations.Type;
...
@Type(type="pg-uuid")
private java.util.UUID itemUuid;

As to why Hibernate doesn’t just make this the default setting, I couldn’t tell you…

UPDATE:
There still seem to be issues using the createNativeQuery method to open objects that have UUID fields. Fortunately, the createQuery method so far has worked fine for me.