Helper class to work with Java UUID

UuidUtil.java

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.util.UUID;

/**
 * This class provides helper methods to work with UUID, for instance, converting UUID into 16-byte
 * array for database column BINARY(16) and vice versa.
 */
public final class UuidUtil
{
    private UuidUtil()
    {
    }

    /**
     * Convert an {@link UUID} into a 16-byte array
     *
     * @param uuid the input {@link UUID}
     * @return a 16-byte array if succeeded, otherwise {@code null}
     */
    public static byte[] asBytes(final UUID uuid)
    {
        if (uuid != null)
        {
            ByteBuffer bb = ByteBuffer.wrap(new byte[16])
                    .order(ByteOrder.BIG_ENDIAN) // BIG_ENDIAN is the default, explicitly set it.
                    .putLong(uuid.getMostSignificantBits())
                    .putLong(uuid.getLeastSignificantBits());
            byte[] bytes = bb.array();
            bb.clear();
            bb = null;
            return bytes;
        }
        return null;
    }

    public static UUID asUuid(final byte[] bytes)
    {
        if (bytes != null)
        {
            ByteBuffer bb = ByteBuffer.wrap(bytes);
            long firstLong = bb.getLong();
            long secondLong = bb.getLong();
            bb = null;
            return new UUID(firstLong, secondLong);
        }
        return null;
    }
}