generic List receiving null value

Question

In my spring appication, I have the following method in amy generic service class (the try/catch blocks were omitted to keep it simple):

@Transactional
public Map<String, List<?>> getListaValores() {
    System.out.println(":"+this.getName());
    Map<String, List<?>> map = new HashMap<String, List<?>>();
    Entidade ent = null;
    List<String> lista = null;

    ent = (Entidade) this.entityClass.newInstance();
    lista = ent.getListaArgumentos();

    for(int i=0; i<lista.size(); i++)
    {
        System.out.println("::"+lista.get(i));
        Class<?> clazz;
        Dao<?> obj;

        String class_name = "com.spring.loja.model."+lista.get(i).toLowerCase()+".persistence."+lista.get(i)+"Home";
        clazz = Class.forName(class_name);
        obj = (Dao<?>) clazz.newInstance();

        if(clazz != null) {
            System.out.println("clazz not null");
            List<?> temp = obj.findAll();
            map.put(lista.get(i), temp);
        } else {
            System.out.println("clazz is null");
            map.put(lista.get(i), null);
        }
    }

    return map;
}

All it's ok until the execution reaches this line:

List<?> temp = obj.findAll();

where temp is receiving null, despite the fact the method findAll in the Dao class being executed, with the correct entity class.

Anyone can see what's wrong here?

And how does the `findAll()` method in `Dao` class looks like? — Rohit Jain, Jul 08 '14 at 18:33
You tagged you question with `spring` but it looks like you a instanciating a new `Dao` at each iteration outside of any application context. How do these `Dao` objects find their configuration ? — Serge Ballesta, Jul 08 '14 at 18:43
@SergeBallesta this way: https://github.com/klebermo/loja.cms/blob/master/src/main/java/com/spring/loja/config/generic/persistence/Dao.java — Kleber Mota, Jul 08 '14 at 18:51
@RohitJain this is my Dao class: https://github.com/klebermo/loja.cms/blob/master/src/main/java/com/spring/loja/config/generic/persistence/Dao.java — Kleber Mota, Jul 08 '14 at 18:52
@SotiriosDelimanolis I know, as I said, I remove the try/catch blocks to keep the code simple, but they exist. — Kleber Mota, Jul 08 '14 at 18:57
@SotiriosDelimanolis my question isn't the same as the other you suggest it's the same (I don't even use `@Autowired` here) — Kleber Mota, Jul 08 '14 at 18:59
Don't be so quick. If you debug, you will probably find that your `Dao`'s `sessionFactory` is `null` and therefore throwing a `NullPointerException` which is caught in `findAll` and returns `null`. — Sotirios Delimanolis, Jul 08 '14 at 19:00

generic List receiving null value

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