Why `floorEntry` and other methods are not accessible in PatriciaTrie?

While implementing an ip-lookup structure, I was trying to maintain a set of keys in a trie-like structure that allows me to search the "floor" of a key (that is, the largest key that is less or equal to a given key). I decided to use Apache Collections 4 PatriciaTrie but sadly, I found that the floorEntry and related methods are not public. My current "dirty" solution is forcing them with reflection (in Scala):

val pt = new PatriciaTrie[String]()
val method = pt.getClass.getSuperclass.getDeclaredMethod("floorEntry", classOf[Object])
method.setAccessible(true)
// and then for retrieving the entry for floor(key) 
val entry = method.invoke(pt, key).asInstanceOf[Entry[String, String]]

Is there any clean way to have the same functionality? Why this methods are not publicly available?