Java.lang.NullPointerException

java.lang.NullPointerException
	at model.repositories.TimeRepository.getLista(TimeRepository.java:37)
	at managedbeans.TimeBean.getTimes(TimeBean.java:65)

public class TimeRepository {
    private EntityManager manager;

    public TimeRepository(EntityManager manager) {
        this.manager = manager;
    }
    
    public void adiciona(Time time){
        this.manager.persist(time);
    }
    
    public Time procura(Long id){
        return this.manager.find(Time.class, id);
    }
    
    public Time atualiza(Time time){
        return this.manager.merge(time);
    }
    
    public List<Time> getLista(){
        Query query = this.manager.createQuery("select t from Time t");
        return query.getResultList();
    }
    
    public void remove(Long id){
        Time time = this.procura(id);
        Query query = this.manager.createQuery("select j from Jogador j");
        List<Jogador> jogadores = query.getResultList();
        
        for (Jogador jogador : jogadores) {
            jogador.setTime(null);
        }
        
        this.manager.remove(time);
    }
}

@ManagedBean
public class TimeBean {
    private Time time = new Time();
    private List<Time> times;
    
    public void adiciona(){
        EntityManager manager = this.getManager();
        TimeRepository repository = new TimeRepository(manager);
        
        if(this.time.getId() == null){
            repository.adiciona(this.time);
        }else{
            repository.atualiza(this.time);
        }
        
        this.time = new Time();
        this.times = null;
    }
    
    public void preparaAlteracao(){
        Map<String, String> params = 
                FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap();
        
        Long id = Long.parseLong(params.get("id"));
        EntityManager manager = this.getManager();
        TimeRepository repository = new TimeRepository(manager);
        this.time = repository.procura(id);
    }
    
    public void remove(){
        Map<String, String> params = 
                FacesContext.getCurrentInstance().getExternalContext().getInitParameterMap();
        Long id = Long.parseLong(params.get("id"));
        EntityManager manager = this.getManager();
        TimeRepository repository = new TimeRepository(manager);
        repository.remove(id);
        this.times = null;
    }
    
    public List<Time> getTimes(){
        if(this.times == null){
            EntityManager manager = this.getManager();
            TimeRepository repository = new TimeRepository(manager);
            this.times = repository.getLista();
        }
        return this.times;
    }
    
    private EntityManager getManager(){
        FacesContext fc = FacesContext.getCurrentInstance();
        ExternalContext ec = fc.getExternalContext();
        HttpServletRequest request = (HttpServletRequest) ec.getRequest();
        return (EntityManager) request.getAttribute("EntityManager");
    }

    public Time getTime() {
        return time;
    }

    public void setTime(Time time) {
        this.time = time;
    }
    
}