latencyQuality

Honestly LatencyQuality.Estimated, and it can never be better.

javax.sound.sampled has no presentation-timestamp API at all: there is no pairing of a frame with the instant it was heard, the way AudioTimestamp gives on Android and AudioTimeStamp gives on CoreAudio. All this sink has is a frame counter, and that counter measures what the JAVA MIXER has consumed, not what the DAC has played, so everything below the mixer (CoreAudio's buffers, an ALSA period chain, the WASAPI endpoint buffer) is invisible to it and is missing from every figure here. It is not LatencyQuality.Unreliable either: the counter does advance at the true playback rate, so the figure tracks reality and is usable once filtered. Estimated is exactly what it is.