Apple doesn't need to put out a smart watch. Putting out a watch with only NFC and BT to any linked iOS device will give them a long life between charges. And they can opt for having a watch face or not with various skin contacts for biometrics.
Does the human body carry any electric current that a worn very-low-power device can use?
Java running Swing fat client is 100% different than Java-plugin-in-a-browser (also running Swing.) The former is 100% in your control. The latter is subject to all the possible hijackings available on the net to inject into it from hidden iframes, etc. It is a disservice to state that it is a security blackhole.