Been raised earlier in this thread a number of times before ... best guess is that Amazon retain some key features for it's own platform. On a slightly different note noticed on streaming Amazon Music that there appears to be a partial drag and drop (similar to windows) on a Playlist queue. Thought it might be a way to permanently rearrange the tracks in the playlist but alas no ... the queue reverts to it's original order after being played. What does happen after a track is played is that the audio quality is displayed in the queue ... but not before it's played. Would be very pleasing if a) it displayed audio quality right from the start, and b) allow you to reorganize your tracks in a playlist permanently with a full drag and drop facility. Maybe you can do this in other ways? Doesn't work with casting Amazon Music unfortunately.
Evidently there is a mismatch with the Java dev-kit... the search engine wants to call a function (a virtual one, expected to be implemented in a child class...) that cannot be found (read: it has not been implemented). Practically a bug; expect a release to fix it.