Ice's blog

Here's an example of such plain java object entity:

package mk.jug.domain;

import javax.persistence.*;

@Entity
public class Cabin implements java.io.Serializable {
/*actually, you don't need to declare it as serializable, but it will allow this class to be passed as a parameter or return values or remote interface methods of session beans.*/

private int id;
private int deckLevel;
private int shipID;
private int bedCount;

@Id
@GeneratedValue
public int getId() {
    return id;
}

public void setId(int id) {
    this.id = id;
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public int getDeckLevel() {
    return deckLevel;
}

public void setDeckLevel(int deckLevel) {
    this.deckLevel = deckLevel;
}

public int getShipID() {
    return shipID;
}

public void setShipID(int shipID) {
    this.shipID = shipID;
}

public int getBedCount() {
    return bedCount;
}

public void setBedCount(int bedCount) {
    this.bedCount = bedCount;
}

o Few Notes:

- The bean class is annotated with @javax.persistence.Entity metadata information. This tells the EJB container that this class is mapped to a persistent (db) entity and that will be managed by an EntityManager service.

- @javax.persistence.Id annotation identifies the property via it's following accessor method as the identification to be used by the EntityManager service to identify and manage the persistent entity

- @javax.persistence.GeneratedValue annotation specifies that either the container or the persistence provider will generate the value when storing/persisting it

- @javax.persistence.Table annotation construct can be also used to specify the name of the table to which this entity class is pairing, it they are different. For example: we can map the Cabin class to BOAT_CABIN table using @Table(name="BOAT_CABIN") annotation

- @javax.persistence.Column metadata information can be used to specify the name of the column to which the class property is mapping, if they are different. For example: we can map the id property to the CABIN_ID db table column, using the @Table(name="CABIN_ID")  annotation

o All of the above annotation constructs can be replaced by a xml descriptor
    - both situations are valid and are left at your disposal. It is a matter of preference    whether to use annotations of xml descriptors.
    - my opinion is that annotations can be very effectively utilized, if used at appropriate places and in a balanced manner.
    
o In a more productive development environment, you can have generators that by the given information in a single xml file can generate both the db schema and the entity classes that pair up together in a synchronized way
   
Have a nice day.

Ice