Problem with Recycler View + CardView + OnCreate in Android

In my code I don't get any error

As I have problems with the init but no matter how many times I give it I can't find what the problem could be I am new to this it should also be emphasized, I have the libraries attached to the gradle and synchronized I have two other java classes where I have the listAdapter.

public class MainActivity extends AppCompatActivity {

List<ListElement> elements;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    init();
}

public void init() {
    elements = new ArrayList<>();
    elements.add(new ListElement("#775447","Gustavo","Chiapas","Activo"));
    elements.add(new ListElement("#772447","Eduardo","Guatemala","Nulo"));
    elements.add(new ListElement("#725447","Jared","Guasave","Inac"));
    elements.add(new ListElement("#785447","Juan","Zacatecas","Inactivo"));
    elements.add(new ListElement("#720447","Ivan","Obregon","Cancelar"));


    ListAdapter listAdapter = new ListAdapter(elements, this);
    RecyclerView recyclerView = findViewById(R.id.listRecyclerView);
    recyclerView.setHasFixedSize(true);
    recyclerView.setLayoutManager(new LinearLayoutManager(this));
    recyclerView.setAdapter(listAdapter);
}

}