NullPointerException when setting Date in Android app

I am following this tutorial for implementing date and time on edit text click.

public class LoadActivity extends AppCompatActivity {
@SuppressLint("StaticFieldLeak")
static EditText DateEdit;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_load);
Toolbar toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
EditText startTimeEditText = (EditText) findViewById(R.id.start_time);   
startTimeEditText.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
showTruitonTimePickerDialog(v);
showTruitonDatePickerDialog(v);
}
});
}  // end onCreate
public void showTruitonDatePickerDialog(View v) {
DialogFragment newFragment = new DatePickerFragment();
newFragment.show(getSupportFragmentManager(), "datePicker");
}
public static class DatePickerFragment extends DialogFragment implements
DatePickerDialog.OnDateSetListener {
@NonNull
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
// Use the current date as the default date in the picker
final Calendar c = Calendar.getInstance();
int year = c.get(Calendar.YEAR);
int month = c.get(Calendar.MONTH);
int day = c.get(Calendar.DAY_OF_MONTH);
// Create a new instance of DatePickerDialog and return it
return new DatePickerDialog(requireActivity(), this, year, month, day);
}
}
@SuppressLint("SetTextI18n")
public void onDateSet(DatePicker view, int year, int month, int day) {
// Do something with the date chosen by the user
DateEdit.setText(day + ":" + (month + 1) + ":" + year);
}
}// end main class

I am able to see the date fragment in my app but when I press ok button the app crashes and I am getting error

> java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.EditText.setText(java.lang.CharSequence)' on a null object reference
at com.thumbsol.accuratemobileassetsmanagament.LoadActivity$DatePickerFragment.onDateSet(LoadActivity.java:300)
at android.app.DatePickerDialog.onClick(DatePickerDialog.java:134)

The line number 300 is DateEdit.setText(day + ":" + (month + 1) + ":" + year);

How can I get rid of this error? Any help would be highly appreciated.

You only define static EditText DateEdit, and also need to get it via findViewById.
for example:

DateEdit = (EditText) findViewById(R.id.date_edit);

That's because you're not setting the value of DateEdit anywhere in your code.

Tip: try to not use a view as static. It may cause leaks.