sequential UUID using current time.Based on https://blog.2ndquadrant.com/sequential-uuid-generators/

UUIDUtils.java

import java.nio.ByteBuffer;
import java.security.SecureRandom;
import java.time.Instant;
import java.util.UUID;

public final class UUIDUtils {
    private static final int UUID_LENGTH = 16;
    private static final int DEFAULT_INTERVAL_LENGTH = 60;
    private static final int DEFAULT_INTERAVL_COUNT = 65536;
    private static volatile SecureRandom numberGenerator = null;

    /**
     * Static factory to generate sequential UUID using current time
     * <p>
     * The timestamp-based sequential UUID generator define the group size
     * and group count based on data extracted from current timestamp.
     * <p>
     * The interval_length (60 seconds by default) is defined as number of
     * seconds where UUIDs share the same prefix). The prefix length is
     * determined by the number of intervals (65536 by default, i.e. 2B).
     * With these parameters the generator wraps around every ~45 days.
     *
     * @return A sequentialy generated {@code UUID} using current time
     */
    public static UUID timeUUID() {
        return timeUUID(DEFAULT_INTERVAL_LENGTH, DEFAULT_INTERAVL_COUNT);
    }

    /**
     * Static factory to generate sequential UUID using current time
     * <p>
     * The timestamp-based sequential UUID generator define the group size
     * and group count based on data extracted from current timestamp.
     *
     * @param intervalLength The number of seconds where {@code UUID} share the same prefix
     * @param intervalCount  Used to derive the prefix length
     * @return A sequentialy generated {@code UUID} using current time
     */
    public static UUID timeUUID(int intervalLength, int intervalCount) {
        assert intervalLength > 1 : "length of interval must be a positive integer";
        assert intervalCount > 1 : "number of intervals must be a positive integer";

        SecureRandom ng = numberGenerator;
        if (ng == null)
            numberGenerator = ng = new SecureRandom();

        int i;
        ByteBuffer buffer = ByteBuffer.allocate(UUID_LENGTH);
        long epoch = Instant.now().getEpochSecond();
        byte[] val = Long.toString(epoch / intervalLength).getBytes();

        int prefixBytes = 0;
        while (intervalCount > 1) {
            intervalCount /= 256;
            prefixBytes++;
        }

        for (i = 0; i < prefixBytes; i++)
            buffer.put(i, val[prefixBytes - 1 - i]);

        byte[] randomBytes = new byte[UUID_LENGTH - prefixBytes];
        ng.nextBytes(randomBytes);
        for (i = 0; i < randomBytes.length; i++)
            buffer.put(i + prefixBytes, randomBytes[i]);

        return new UUID(buffer.getLong(), buffer.getLong());
    }
}