public class Uid {    private static final String machineIdString = Integer.toHexString(new Object().hashCode());    private static final AtomicInteger globalCount = new AtomicInteger(0);    private final int count = globalCount.incrementAndGet();    private final long time = System.currentTimeMillis();    /**     * Generates a new identifier.     */    private Uid() {        super();    }    /**     * Generates a new identifier String.     */    public static String generateUidString() {        String idString = new Uid().toString();        return idString;    }    /**     * @see Object#toString()     */    public String toString() {        String timeString = Long.toHexString(time);        String countString = Integer.toHexString(count);        return machineIdString + "_" + timeString + "_" + countString;    }}