@Entity
public class Request implements java.io.Serializable {

@Version
@Temporal(TemporalType.TIMESTAMP)
@Column(name = "LAST_UPDATE_TIMESTAMP", length = 26)
public Date getLastUpdateTimestamp() {
    return this.lastUpdateTimestamp;
}

request.setStatus(status);
request.setLastUpdateTimestamp(currenttimestamp);
s.save(request);

update REQUEST ... where ID=? and LAST_UPDATE_TIMESTAMP=?