Problema com hibernate

Pessoal to com o seguinte problema tenho uma classe gerada pelo netbeans, para utilização com hibernate, jsf etc. O problema é que não consigo adicionar novos atributos na classe por eles não existirem no banco, alguém pode me dizer como faço isso?

Segue abaixo a classe o atributo que estou querendo adicionar é o is_running.

Msg de erro: Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown column ‘externalmo0_.is_running’ in ‘field list’

/**
*

• @author artur
  
  */
  
  @Entity
  
  @Table(name = “externalmonitor”)
  
  @NamedQueries({
  
  @NamedQuery(name = “Externalmonitor.findAll”, query = “SELECT e FROM Externalmonitor e”),
  
  @NamedQuery(name = “Externalmonitor.findById”, query = “SELECT e FROM Externalmonitor e WHERE <a href="http://e.id">e.id</a> = :id”),
  
  @NamedQuery(name = “Externalmonitor.findByIp”, query = “SELECT e FROM Externalmonitor e WHERE e.ip = :ip”),
  
  @NamedQuery(name = “Externalmonitor.findByPort”, query = “SELECT e FROM Externalmonitor e WHERE e.port = :port”),
  
  @NamedQuery(name = “Externalmonitor.findByStatus”, query = “SELECT e FROM Externalmonitor e WHERE e.status = :status”),
  
  @NamedQuery(name = “Externalmonitor.findByCreationDate”, query = “SELECT e FROM Externalmonitor e WHERE e.creationDate = :creationDate”),
  
  @NamedQuery(name = “Externalmonitor.findByLastCheck”, query = “SELECT e FROM Externalmonitor e WHERE e.lastCheck = :lastCheck”),
  
  @NamedQuery(name = “Externalmonitor.findByCheckTime”, query = “SELECT e FROM Externalmonitor e WHERE e.checkTime = :checkTime”)})
  
  public class Externalmonitor implements Serializable {
  
  private static final long serialVersionUID = 1L;
  
  @Id
  
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  
  <a class="mention" href="/u/basic">@Basic</a>(optional = false)
  
  @Column(name = “id”)
  
  private Integer id;
  
  <a class="mention" href="/u/basic">@Basic</a>(optional = false)
  
  @Column(name = “ip”)
  
  private String ip;
  
  <a class="mention" href="/u/basic">@Basic</a>(optional = false)
  
  @Column(name = “port”)
  
  private Integer port;
  
  <a class="mention" href="/u/basic">@Basic</a>(optional = false)
  
  @Column(name = “status”)
  
  private boolean status;
  
  <a class="mention" href="/u/basic">@Basic</a>(optional = false)
  
  @Column(name = “creation_date”)
  
  @Temporal(TemporalType.TIMESTAMP)
  
  private Date creationDate;
  
  @Column(name = “last_check”)
  
  @Temporal(TemporalType.TIMESTAMP)
  
  private Date lastCheck;
  
  @Column(name = “check_time”)
  
  private Integer checkTime;
  
  @JoinColumn(name = “account_id”, referencedColumnName = “id”)
  
  @ManyToOne(optional = false)
  
  private Account accountId;
  
  @OneToMany(mappedBy = “externalmonitorId”)
  
  private Set<Anomaly> anomalySet;
  

  [color=red]private boolean is_running;[/color]