Sorting is not working in datatable in PrimeFaces?

Question

Sorting is not working in datatable in PrimeFaces. Please suggest.

See below my .xhtml file

Answer 1

My Service had:

public List<PlayerEntity> getAllPlayers() {
    return playerDao.readAll();
}

but that was wrong, because when I was calling getAllPlayers() from table

<p:dataTable id="data" value="#{myBean.allPlayers}"/>

I got from DAO refreshed data but still unordered. Instead of that I've created List field and method to update the List

private List<PlayerEntity> allPlayers = new ArrayList<PlayerEntity>();  

public void updateAllPlayers(){
    this.allPlayers = playerDao.readAll();
}

which method I'm running on bean initialization

public void setPlayerDao(PlayerDao playerDao) {
    this.playerDao = playerDao;
    updateAllPlayers();
}

and after Add, Delete or Modiffy the List

public boolean createPlayer(PlayerEntity playerEntity) {
    (...)
    updateAllPlayers();
    return true;
}

Now my Service has

public List<PlayerEntity> getAllPlayers() {
    return this.allPlayers;
}

and that solved my problem with sorting data in Primefaces table.