alert dialog on android

1new AlertDialog.Builder(this)
2    .setTitle("Closing application")
3    .setMessage("Are you sure you want to exit?")
4    .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
5          @Override
6          public void onClick(DialogInterface dialog, int which) {
7
8          }
9     }).setNegativeButton("No", null).show();
10