How to read a file and save data in android sqlite database [duplicate]

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• What is a Null Pointer Exception, and how do I fix it? 12 answers

I am having some trouble reading a file and saving the data from the file into sqlite db. I get this error:

Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String com.example.testPreject.bdd.Lien.getLiencomplet() on a null object reference

public class MainActivity extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        LienBDD lienBdd = new LienBDD(this);
        lienBdd.open();
        Lien lienFromBdd = lienBdd.getLienWithTitre("google");
        String test = lienFromBdd.getLiencomplet().toString();

        lienBdd.close();

        Toast.makeText(this, test, Toast.LENGTH_LONG).show();
    }
}