Question

i am making a sample program in hibernate follow this tutorial:
http://www.myeclipseide.com/documentation/quickstarts/hibernateintroduction/

using reverse engineering, i have created this method.
EventsDAO.java:

public Events findById(com.hibernate.EventsId i) {
    log.debug("getting Events instance with id: " + i);
    try {
        Events instance = (Events) getSession().get(
                "com.hibernate.Events", i);
        return instance;
    } catch (RuntimeException re) {
        log.error("get failed", re);
        throw re;
    }
}

and calling from main class makiing this method:

private static void listEvents()
{
    EventsDAO dao= new EventsDAO();
    Events events= dao.findById(1);
    printEvents("Printing User,", events);
dao.getSession().close();
}

it give me error on : Events events= dao.findById(1);
because here, i am passing int. and in EventsDAO.java, its type is EventsID.

please suggest.

as surlac suggest,
now it is giving exception:
Exception in thread “main” org.hibernate.id.IdentifierGenerationException: ids for this class must be manually assigned before calling save(): com.hibernate.Events

private static void addEvents()
{
    Events events= new Events();
    events.setUid(1);
    events.setName("abc");
    events.setDuration(123);
    EventsDAO dao= new EventsDAO();
    Transaction tx=dao.getSession().beginTransaction();
dao.save(events);
tx.commit();
dao.getSession().close();
}

it is giving exception on this line:

dao.save(events);

Here is Events.hbm.xml file: <?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!--
Mapping file autogenerated by MyEclipse Persistence Tools
-->
<hibernate-mapping>
<class name="com.hibernate.Events" table="EVENTS" schema="APP">
<composite-id name="id" class="com.hibernate.EventsId">
<key-property name="uid" type="java.lang.Long">
<column name="UID" />
</key-property>
<key-property name="name" type="java.lang.String">
<column name="NAME" length="20" />
</key-property>
<key-property name="duration" type="java.lang.Integer">
<column name="DURATION" />
</key-property>
</composite-id>
</class>
</hibernate-mapping>

please help.

Answer 1

Try to use Integer as an ID, unless you use composite keys:

    public Events findById( java.lang.Integer id) {
        log.debug("getting Events instance with id: " + id);
        try {
            Events instance = (Events) getSession()
                    .get("com.hibernate.Events", id);
            return instance;
        } catch (RuntimeException re) {
            log.error("get failed", re);
            throw re;
        }
    }