Para trabajar con Bean debes crear una MyFactoryData y luego agregar el metodo createBeanCollection().
Ejemplo:
package com.datos;
import java.util.Vector;
import com.modelo.Comuna;
public class FactoriaDatos {
public static Vector createBeanCollection() {
java.util.Vector coll = new java.util.Vector();
Comuna comuna = new Comuna();
coll.add(new Comuna(1,1,100,»Santiago»));
coll.add(new Comuna(2,1,200,»San Bernardo»));
coll.add(new Comuna(3,1,300,»Maipu»));
coll.add(new Comuna(4,1,400,»Peñalolen»));
coll.add(new Comuna(5,1,500,»La Florida»));
return coll;
}
}
Ver documentacion aquí:
http://www.java2s.com/Open-Source/Java-Document/Report/iReport-2.0.5/it/businesslogic/ireport/connection/SampleJRDataSourceFactory.java.java-doc.htm
http://knol.google.com/k/jasper-reports-working-with-beans-and-sub-report#