NullPointerException: Attempt to invoke virtual method 'java.lang.Boolean'

I have a splash activity in my app and intro .. What i wanna do is showing intro activity only in the first run so i used share preference to do so

Here is my codes

Splash Activity

Handler handler = new Handler();
    handler.postDelayed(() -> {
        if (sharedPref != null && !sharedPref.loadIntroDone()) {
            Intent intent = new Intent(SplashActivity.this, IntroSliders.class);
    startActivity(intent);
    finish();
        } else {
            Intent intent = new Intent(SplashActivity.this, MainActivity.class);
    startActivity(intent);
    finish();
        }
    }, 4000);

Shared Preference

public Boolean loadIntroDone() {
    return (mySharedPref == null) || mySharedPref.getBoolean("IntroDone", false);
}

It causes crash after splash activity appear

Error

java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Boolean com.example.example.SharedPref.loadIntroDone()' on a null object reference