@Version
@Setter(AccessLevel.NONE)
@Column(name = "VERSION")
private long version;

Exception message is : Object of class [com.myPackage.WorkQueue] with identifier [9074]: optimistic locking failed; nested exception is org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect) : [com.myPackage.WorkQueue#9074]

@Override
@Transactional(isolation = Isolation.READ_COMMITTED, rollbackFor=Exception.class, readOnly=false)
public WorkQueue retrieveWorkQueueItemByStatus(WorkQueueStatusEnum workQueueStatus) {
    return workQueueRepository.retrieveWorkQueueItemByStatus(workQueueStatus);
}

@Override
public WorkQueue retrieveWorkQueueItemByStatus(WorkQueueStatusEnum workQueueStatus) {
    log.debug("Start - Attempting to select a " + workQueueStatus + " workQueue item in retrieveWorkQueueItemByStatus()");

    try {
        String sql = "SELECT a FROM WorkQueue a WHERE workQueueStatus = :workQueueStatus ORDER BY idWorkQueue ASC";
        TypedQuery<WorkQueue> query = em.createQuery(sql, WorkQueue.class).setParameter("workQueueStatus", workQueueStatus)
        .setFirstResult(0).setMaxResults(1);
        WorkQueue workQueue = (WorkQueue) query.getSingleResult();
        if (workQueue != null) {
            workQueue.setWorkQueueStatus(WorkQueueStatusEnum.IN_PROGRESS);
            WorkQueue updatedWorkQueue = em.merge(workQueue);
            log.debug("Finish - selected the following workQueue item "+ workQueue.getIdWorkQueue() + " with the Audit Event Key from retrieveWorkQueueItemByStatus() : " + updatedWorkQueue.getAuditEventKey());
            return updatedWorkQueue;
        }
    } catch (IllegalArgumentException iae) {
        log.error("An IllegalArgumentException occured in workQueueRepositoryImpl.retrieveWorkQueueItemByStatus() attempting to execute query : " + sql + ". Exception message is : " + iae.getMessage());
    } catch(Exception ex) {
        log.error("An Exception occured in workQueueRepositoryImpl.retrieveWorkQueueItemByStatus() executing query : " + sql + ". Exception message is : " + ex.getMessage());
    }
    log.debug("Finish - returning null from retrieveWorkQueueItemByStatus()");
    return null;
}