Error trying to fill a listview

I'm trying to populate my listview so

historicos=banco.getAllH(); 
ArrayAdapter<HistoricoObjeto> itens = new ArrayAdapter<HistoricoObjeto>(this, 
            android.R.layout.simple_list_item_1, historicos); 

this.lista.setAdapter(itens);
this.lista.setClickable(true);
registerForContextMenu(lista);

More is giving null pointer exception error in this line

this.lista.setAdapter(itens);

I'm going to put the HistoticoObjeto class to be clearer what and the object I use

public class HistoricoObjeto implements Serializable{

    private String id;
    public String datahora;
    public String mensagem;

    public HistoricoObjeto() {

    }

    public HistoricoObjeto(String id, String datahora, String mensagem) {
        super();
        this.setId(id);
        this.setDatahora(datahora);
        this.setMensagem(mensagem); 
    }
}

Can anyone tell me where I'm going wrong?

11-25 12:22:02.809: E/AndroidRuntime(11457): FATAL EXCEPTION: main
11-25 12:22:02.809: E/AndroidRuntime(11457): java.lang.RuntimeException: Unable to resume activity {com.ilgner.chegouahora/com.ilgner.chegouahora.Historico}: java.lang.NullPointerException
11-25 12:22:02.809: E/AndroidRuntime(11457):    at android.app.ActivityThread.performResumeActivity(ActivityThread.java:2124)
11-25 12:22:02.809: E/AndroidRuntime(11457):    at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:2139)
11-25 12:22:02.809: E/AndroidRuntime(11457):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1672)
11-25 12:22:02.809: E/AndroidRuntime(11457):    at android.app.ActivityThread.access$1500(ActivityThread.java:117)
11-25 12:22:02.809: E/AndroidRuntime(11457):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:935)
11-25 12:22:02.809: E/AndroidRuntime(11457):    at android.os.Handler.dispatchMessage(Handler.java:99)
11-25 12:22:02.809: E/AndroidRuntime(11457):    at android.os.Looper.loop(Looper.java:130)
11-25 12:22:02.809: E/AndroidRuntime(11457):    at android.app.ActivityThread.main(ActivityThread.java:3687)
11-25 12:22:02.809: E/AndroidRuntime(11457):    at java.lang.reflect.Method.invokeNative(Native Method)
11-25 12:22:02.809: E/AndroidRuntime(11457):    at java.lang.reflect.Method.invoke(Method.java:507)
11-25 12:22:02.809: E/AndroidRuntime(11457):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
11-25 12:22:02.809: E/AndroidRuntime(11457):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625)
11-25 12:22:02.809: E/AndroidRuntime(11457):    at dalvik.system.NativeStart.main(Native Method)
11-25 12:22:02.809: E/AndroidRuntime(11457): Caused by: java.lang.NullPointerException
11-25 12:22:02.809: E/AndroidRuntime(11457):    at com.ilgner.chegouahora.Historico.onResume(Historico.java:62)
11-25 12:22:02.809: E/AndroidRuntime(11457):    at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1150)
11-25 12:22:02.809: E/AndroidRuntime(11457):    at android.app.Activity.performResume(Activity.java:3832)
11-25 12:22:02.809: E/AndroidRuntime(11457):    at android.app.ActivityThread.performResumeActivity(ActivityThread.java:2114)
11-25 12:22:02.809: E/AndroidRuntime(11457):    ... 12 more




    @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_historico);
    this.lista = (ListView)findViewById(R.id.lvContatos);
    this.banco = new Banco(getApplicationContext());
    HistoricoObjeto historico = new HistoricoObjeto();
    brCollator = Collator.getInstance(new Locale("pt", "BR"));
}

@Override
protected void onResume() {
    super.onResume();
    historicos=banco.getAllH();

    historicos=ordena(brCollator, historicos);
    ArrayAdapter<HistoricoObjeto> itens = new ArrayAdapter<HistoricoObjeto>(this, 
            android.R.layout.simple_list_item_1, historicos){ 
        @Override
        public View getView (int position, View convertView, ViewGroup parent) {

                View view = super.getView(position, convertView, parent);

                // Como o simple_list_item_1 retorna um TextView, esse cast pode ser feito sem problemas
                ((TextView) view).setTextColor(Color.BLACK);

                return view;
            }}; 

    Log.e("", ""+itens.getCount());
    this.lista.setAdapter(itens);
    this.lista.setClickable(true);
    registerForContextMenu(lista);

}

Strange stopped this error there, and I did not do anything, but I used this code there in another list, but it was with Historico it was with a class Person that had a name, and phone there in the list, but now I'm not sure how to make one of the variables appear in the list, the history class has a date and time and a message I wanted to make the two or one