Java Collection overwrites all elements when using add()

[Marcel Jacome]

Hi guys , i have a problem which has kept me banging my head against a brick wall all day. I am using a collection to store objects
so later i can display them in a rich:dataTable component.

I have an iterator in a for loop so as to initialize an object (detalle). Once an object is initialized, it gets stored in a collection
using the add(Object) method , problem is , the whole collection is overwritten by the most recent object inserted by the add() method.

It goes something like this:

Iteration 1
object detalle1 is initialized
object detalle1 is added to a collection
collection's size is one and holds object detalle1

Iteration 2
object detalle2 is initialized
object detalle2 overwrites the first slot
object detalle2 is added to an auxiliary collection
Now instead of having Collection: detalle1 , detalle2 , i have a duplicate of object detalle2 and the first object is overwritten.
collection's size is two and holds detalle2 , detalle2 (detalle1 has been overwritten)

If I continue with more iterations , the last object is added at the end , but overwrites all the rest of the objects in the collection.So i end
up with the last object all over the collection.

I tried advancing the pointer with Collection.iterator.next() to no avail. This keeps happening and I dont know what is going on.

Please Help!!!


This is the code

 public void poblarDetalles(Collection<Cargos> cargos){

	log.info("poblando detalles de objetos retornados "+cargos.size()+" elementos");

	CargosAplicacionBeanDetalles detalle = new CargosAplicacionBeanDetalles();

	ArrayList<CargosAplicacionBeanDetalles> itemDetallesAux=new ArrayList<CargosAplicacionBeanDetalles>();

	int nIteraciones=0;

	for (Iterator<Cargos> it=cargos.iterator(); it.hasNext(); ) {

			Cargos elemento = it.next();

			detalle.setCodcar(elemento.getCodcar());

			detalle.setCodfunres(elemento.getCodfunres());

			detalle.setCodsolafi(elemento.getCodsolafi());

			detalle.setCodsuc(elemento.getCodsuc());

			detalle.setCodtippla(elemento.getCodtippla());

			detalle.setCodtipsolafi(elemento.getCodtipsolafi());

			detalle.setDescar(elemento.getDescar());

			detalle.setEstcar(elemento.getEstcar());

			detalle.setFecbol(elemento.getFecbol());

			detalle.setFecpro(elemento.getFecpro());

			detalle.setFecregcar(elemento.getFecregcar());

			detalle.setFinper(elemento.getFinper());

			detalle.setIniper(elemento.getIniper());

			detalle.setMesper(elemento.getMesper());

			detalle.setNumbol(elemento.getNumbol());

			detalle.setPorapl(elemento.getPorapl());

			detalle.setRucemp(elemento.getRucemp());

			detalle.setSecpla(elemento.getSecpla());

			detalle.setTipper(elemento.getTipper());

			detalle.setSeleccionado(true);

			detalle.setAplicado(false);

	try {


			detalle.toString();
            //Here object detalle is added to an auxiliary collection. This is the collection (itemDetallesAux) where all elements are being overwritten by the most recent addition
			Boolean resultadoCopiaDetalles=itemDetallesAux.add(detalle);


	//check the result 

	if(resultadoCopiaDetalles==true){

			log.info("si se copio a coleccion temporal");

			itemDetallesAux.toString();

			log.info("numero de objetos en coleccion temporal es "+itemDetallesAux.size());

	}

	} catch (Exception e) {


			log.info(e.getStackTrace());

			log.info("condicion de error "+e.getMessage());

			log.info("condicion de error "+e.getCause());

	}

			nIteraciones=nIteraciones +1;

			log.info("iteracion "+nIteraciones);

	}//final de for

	//Auxiliary collection is added to managed property using addAll()
	Boolean resultadoCopiaTodos=itemDetalle.addAll(itemDetallesAux);
    //check result
	if(resultadoCopiaTodos){

			log.info("si se copio a coleccion definitiva");

			log.info("numero de iteraciones es "+nIteraciones);

			log.info("objeto detalle es "+itemDetalle.size());

			

	}

	}
	   

Thanks in advance

[Christophe Verré]

You are using the same detalle object all along. Maybe moving "CargosAplicacionBeanDetalles detalle = new CargosAplicacionBeanDetalles();" into the for loop would solve your problem ?

[Marcel Jacome]

Thanks very much Christophe , your advice makes a lot of sense. i will give it a try and let you know.

[Campbell Ritchie]

And always avoid == true and == false. Use if (boo) . . . not if (boo == true). Use if (!boo) . . . not if (boo == false).

[Marcel Jacome]

Thanks Christophe, it solved my problem and thanks Ritchie for the advice , you are totally right. A nice day to you both.