EJB (Enterprise Java Beans) - EJB declaracion de métodos

Hola soy nuevo con EJB y estoy siguiendo un ejemplo en el que se definen 3 ficheros:
CabinRemote.java, CabinHomeRemote.java, CabinBean.java

Lo que no se es por qué no se implementan los métodos abstractos de los tres archivos.

CabinRemote.java

public interface CabinRemote extends javax.ejb.EJBObject {
public String getName() throws RemoteException;
public void setName(String str) throws RemoteException;
public int getDeckLevel() throws RemoteException;
public void setDeckLevel(int level) throws RemoteException;
public int getShipId() throws RemoteException;
public void setShipId(int sp) throws RemoteException;
public int getBedCount() throws RemoteException;
public void setBedCount(int bc) throws RemoteException;
}

CabinHomeRemote.java

public interface CabinHomeRemote extends javax.ejb.EJBHome {
public CabinRemote create(Integer id) throws CreateException, RemoteException;
public CabinRemote findByPrimaryKey(Integer pk) throws FinderException, RemoteException;
}

CabinBean.java

public abstract class CabinBean implements javax.ejb.EntityBean {

public Integer ejbCreate(Integer id) throws CreateException {
this.setId(id);
return null;
}

public void ejbPostCreate(Integer id) {}
public abstract void setId(Integer id);
public abstract Integer getId();
public abstract void setShipId(int ship);
public abstract int getShipId();
public abstract void setName(String name);
public abstract String getName();
public abstract void setBedCount(int count);
public abstract int getBedCount();
public abstract void setDeckLevel(int level);
public abstract int getDeckLevel();
public void setEntityContext(EntityContext ctx) {}
public void unsetEntityContext() {}
public void ejbActivate() {}
public void ejbPassivate() {}
public void ejbLoad() {}
public void ejbStore() {}
public void ejbRemove() {}
}

Gracias