@Override public List<Camara> getCamerasByUser(Usuario user) { Collection<Foto> CollectionPhoto = user.getFotoCollection(); List<Camara> allCameras = new ArrayList<>(); for (Foto f : CollectionPhoto) { allCameras.add(f.getIdCamara()); } List<Camara> filterCameras = new ArrayList<>(); for (int i = 0; i < allCameras.size(); i++) { if (!filterCameras.contains(allCameras.get(i)) && allCameras.get(i) != null) { filterCameras.add(allCameras.get(i)); } } return filterCameras; }