java/PHP bridge, returning List into PHP

Question

Currently i am new into PHP, and I'm using Java/PHP bridge in my project. I need to call java method from PHP script

 public List<Notification> getNotifications()
  {
    return getNotifications(50);
  }

which returns List type, and as I know PHP doesn't support this data type. So the question is, which is the best way to save result in PHP variable (or another structure).

$notifications =   $some_instantiated_object->getNotifications();

this one causes exception