public Media(Uri uri, String path){

this.uri = uri;
this.path = path;
}

private final LinkedList<Media> mediasList;

void setMediasListAndStartFirstActivity(){

    while (cursor != null && cursor.moveToNext()) {

      Uri uri = Uri.withAppendedPath(contentUri, cursor.getString(cursor.getColumnIndexOrThrow(Images.Media._ID)));
      String path = cursor.getString(cursor.getColumnIndexOrThrow(Images.Media.DATA));

      mediasList.add(new Media(uri, path));
    }

Intent i = new Intent(requireActivity(), FirstActivity.class);
i.putExtra("mediasList", mediasList);
startActivity(i);

 }

Bundle extras = getIntent().getExtras();
mediasList = (ArrayList<Media>) getIntent().getExtras().get("mediasList");

   for(Media media : mediasList)
    boolean hasMedia = new File(media.getPath()).isFile(); // --> all medias return true

    void transferAllMediasToSecondActivity(){
        Intent i = new Intent(FirstActivity.this, SecondActivity.class);
        i.putExtra("mediasList", mediasList);
        startActivity(i);
    }

Bundle extras = getIntent().getExtras();
mediasList = (ArrayList<Media>) getIntent().getExtras().get("mediasList");

  for(Media media : mediasList)
    boolean hasMedia = new File(media.getPath()).isFile(); // --> all medias return false. All medias are not readable