MainActivity.class (getStudents)

public class MainActivity extends AppCompatActivity {

    private final String TAG = MainActivity.class.getName();

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

        Realm.init(getApplicationContext());

        for (Student student : StudentManager.getInstance().getStudents()) {
            Log.d(TAG, student.getStudentId() + "\n"
                    + student.getFirstName() + "\t" + student.getLastName() + "\n"
                    + student.getGender() + "\n"
                    + student.getAge() + "\n"
                    + student.getCity() + "\n");
        }
    }
}