The following is an analog (uses hands) clock that uses buffered drawing to increase speed.
Tutorial Details:
In buffered drawing some or all of an images is computed once and stored so that it doesn't have to be redrawn later. In this program the clock face is drawn only once, and the hands are computed.
Digital Clock developed in java
This digital clock displays the local time in 24-hour format. Hours, minutes and seconds are displayed as 7-segment BCD-LED digits with segments tapered at both ends.