Android targetSdkVersion 23 checkSelfPermission method

I am facing checking permission value in Android 6.0 (API 23). Always get 0 value even permission enable or disable from app's settings.

Below is step which I taken.

Contact permission manually disable from device settings->apps-> My apps-> permission -> Disable contact permission.

Still In Android 6.0 every time got 0 value when execute below line of code.

ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_CONTACTS)

Below is my code. which I define in main launcher activity class

// Identifier for the permission request
private static final int WRITE_CONTACTS_PERMISSIONS_REQUEST = 9;
........

@Override
public void onCreate(Bundle savedInstanceState) {
....
if (android.os.Build.VERSION.SDK_INT <= android.os.Build.VERSION_CODES.LOLLIPOP_MR1)
    {
        sharedPreferencesEditor.putBoolean(getString(R.string.ALLOW_ACCESS_PHONEBOOK), true);
        sharedPreferencesEditor.commit();
    }
    else {
        getPermissionToReadUserContacts();
    }
....

}


// Called when the user is performing an action which requires the app to read the
// user's contacts
public void getPermissionToReadUserContacts() {
    // 1) Use the support library version ContextCompat.checkSelfPermission(...) to avoid
    // checking the build version since Context.checkSelfPermission(...) is only available
    // in Marshmallow
    // 2) Always check for permission (even if permission has already been granted)
    // since the user can revoke permissions at any time through Settings
    if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_CONTACTS)
            != PackageManager.PERMISSION_GRANTED) {

        // The permission is NOT already granted.
        // Check if the user has been asked about this permission already and denied
        // it. If so, we want to give more explanation about why the permission is needed.
        if (shouldShowRequestPermissionRationale(
                Manifest.permission.WRITE_CONTACTS)) {
            // Show our own UI to explain to the user why we need to read the contacts
            // before actually requesting the permission and showing the default UI
        }

        // Fire off an async request to actually get the permission
        // This will show the standard permission request dialog UI
        requestPermissions(new String[]{Manifest.permission.WRITE_CONTACTS},
                WRITE_CONTACTS_PERMISSIONS_REQUEST);
    }
}

// Callback with the request from calling requestPermissions(...)
@Override
public void onRequestPermissionsResult(int requestCode,
                                       @NonNull String permissions[],
                                       @NonNull int[] grantResults) {
    // Make sure it's our original READ_CONTACTS request
    if (requestCode == WRITE_CONTACTS_PERMISSIONS_REQUEST) {
        if (grantResults.length == 1 &&
                grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            Toast.makeText(this, "Write Contacts permission granted", Toast.LENGTH_SHORT).show();
        } else {
            Toast.makeText(this, "Write Contacts permission denied", Toast.LENGTH_SHORT).show();
        }
    } else {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    }
}