I solved my issue in this case:
public void saveNonExistingGroupContacts(GroupItem group, ArrayList<ContactItem> contacts)
{
DatabaseHandler db = new DatabaseHandler(context.getApplicationContext());
Dao<GroupItem,Integer> daoGroup = null;
Dao<ContactItem,Integer> daoContact = null;
GroupItem newGroup;
try {
daoGroup = db.getGroupDao();
daoContact= db.getContactDao();
UpdateBuilder<ContactItem, Integer> contactUpdateBuilder = daoContact.updateBuilder();
UpdateBuilder<GroupItem, Integer> groupUpdateBuilder = daoGroup.updateBuilder();
daoGroup.createIfNotExists(group);
newGroup = daoGroup.queryForId(group.getId());
ForeignCollection<ContactItem> fAp =
daoGroup.getEmptyForeignCollection(Constants.GROUP_CONTACTS_LIST);
for (ContactItem contact: contacts)
{
contact.setContactGroup(group);
newGroup.setContact(contact);
newGroup.setCount(newGroup.getCount()+1);
contactUpdateBuilder.updateColumnValue(Constants.CONTACT_GROUP,newGroup);
groupUpdateBuilder.updateColumnValue(Constants.GROUP_CONTACT,contact);
}
contactUpdateBuilder.update();
groupUpdateBuilder.update();
}
catch(Exception e)
{
e.printStackTrace();
}
}