Создание и открытие сессии в Hibernate

Configuration configuration = new Configuration();

public class BuildSessionFactory {
    private static final SessionFactory ourSessionFactory;
 
    static {
        try {
            Configuration configuration = new Configuration();
            configuration.configure();
 
            ourSessionFactory = configuration.buildSessionFactory();
        } catch (Throwable ex) {
            throw new ExceptionInInitializerError(ex);
        }
    }
 
    public static Session getSession() throws HibernateException {
        return ourSessionFactory.openSession();
    }
 
    public static void main(final String[] args) throws Exception {
        final Session session = getSession();
        try {
            System.out.println("querying all the managed entities...");
            final Metamodel metamodel = session.getSessionFactory().getMetamodel();
            for (EntityType<?> entityType : metamodel.getEntities()) {
                final String entityName = entityType.getName();
                final Query query = session.createQuery("from " + entityName);
                System.out.println("executing: " + query.getQueryString());
                for (Object o : query.list()) {
                    System.out.println("  " + o);
                }
            }
        } finally {
            session.close();
        }
    }
}

static {
        try {
            Configuration configuration = new Configuration();
            configuration.configure();
 
            ourSessionFactory = configuration.buildSessionFactory(); // ourSessionFactory=null
        } catch (Throwable ex) {
            throw new ExceptionInInitializerError(ex);
        }
    }

@Entity
@Table(name = "employee", schema = "staffdepartment", catalog = "")
public class EmployeeEntity {
    private int idEmployee;
    private String firstName;
    private String lastName;
    private String patronymicName;
    private String passwordData;
    private Date dateBirth;
    private String pol;
    private Integer inn;
    private Integer idPostAndDepartment;
    private Date dateEmployment;
    private Collection<ChildrenEntity> childrenByIdEmployee;
    private PostanddepartmentEntity postanddepartmentByIdPostAndDepartment;
 
    @Id
    @Column(name = "id_Employee", nullable = false)
    public int getIdEmployee() {
        return idEmployee;
    }
 
    public void setIdEmployee(int idEmployee) {
        this.idEmployee = idEmployee;
    }
 
    @Basic
    @Column(name = "FirstName", nullable = true, length = 30)
    public String getFirstName() {
        return firstName;
    }
 
    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }
 
    @Basic
    @Column(name = "LastName", nullable = true, length = 30)
    public String getLastName() {
        return lastName;
    }
 
    public void setLastName(String lastName) {
        this.lastName = lastName;
    }
 
    @Basic
    @Column(name = "PatronymicName", nullable = true, length = 30)
    public String getPatronymicName() {
        return patronymicName;
    }
 
    public void setPatronymicName(String patronymicName) {
        this.patronymicName = patronymicName;
    }
 
    @Basic
    @Column(name = "PasswordData", nullable = true, length = 100)
    public String getPasswordData() {
        return passwordData;
    }
 
    public void setPasswordData(String passwordData) {
        this.passwordData = passwordData;
    }
 
    @Basic
    @Column(name = "DateBirth", nullable = true)
    public Date getDateBirth() {
        return dateBirth;
    }
 
    public void setDateBirth(Date dateBirth) {
        this.dateBirth = dateBirth;
    }
 
    @Basic
    @Column(name = "Pol", nullable = true, length = 3)
    public String getPol() {
        return pol;
    }
 
    public void setPol(String pol) {
        this.pol = pol;
    }
 
    @Basic
    @Column(name = "INN", nullable = true)
    public Integer getInn() {
        return inn;
    }
 
    public void setInn(Integer inn) {
        this.inn = inn;
    }
 
    @Basic
    @Column(name = "id_PostAndDepartment", nullable = true)
    public Integer getIdPostAndDepartment() {
        return idPostAndDepartment;
    }
 
    public void setIdPostAndDepartment(Integer idPostAndDepartment) {
        this.idPostAndDepartment = idPostAndDepartment;
    }
 
    @Basic
    @Column(name = "DateEmployment", nullable = true)
    public Date getDateEmployment() {
        return dateEmployment;
    }
 
    public void setDateEmployment(Date dateEmployment) {
        this.dateEmployment = dateEmployment;
    }
 
    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
 
        EmployeeEntity that = (EmployeeEntity) o;
 
        if (idEmployee != that.idEmployee) return false;
        if (firstName != null ? !firstName.equals(that.firstName) : that.firstName != null) return false;
        if (lastName != null ? !lastName.equals(that.lastName) : that.lastName != null) return false;
        if (patronymicName != null ? !patronymicName.equals(that.patronymicName) : that.patronymicName != null)
            return false;
        if (passwordData != null ? !passwordData.equals(that.passwordData) : that.passwordData != null) return false;
        if (dateBirth != null ? !dateBirth.equals(that.dateBirth) : that.dateBirth != null) return false;
        if (pol != null ? !pol.equals(that.pol) : that.pol != null) return false;
        if (inn != null ? !inn.equals(that.inn) : that.inn != null) return false;
        if (idPostAndDepartment != null ? !idPostAndDepartment.equals(that.idPostAndDepartment) : that.idPostAndDepartment != null)
            return false;
        if (dateEmployment != null ? !dateEmployment.equals(that.dateEmployment) : that.dateEmployment != null)
            return false;
 
        return true;
    }
 
    @Override
    public int hashCode() {
        int result = idEmployee;
        result = 31 * result + (firstName != null ? firstName.hashCode() : 0);
        result = 31 * result + (lastName != null ? lastName.hashCode() : 0);
        result = 31 * result + (patronymicName != null ? patronymicName.hashCode() : 0);
        result = 31 * result + (passwordData != null ? passwordData.hashCode() : 0);
        result = 31 * result + (dateBirth != null ? dateBirth.hashCode() : 0);
        result = 31 * result + (pol != null ? pol.hashCode() : 0);
        result = 31 * result + (inn != null ? inn.hashCode() : 0);
        result = 31 * result + (idPostAndDepartment != null ? idPostAndDepartment.hashCode() : 0);
        result = 31 * result + (dateEmployment != null ? dateEmployment.hashCode() : 0);
        return result;
    }
 
    @OneToMany(mappedBy = "employeeByIdEmployee")
    public Collection<ChildrenEntity> getChildrenByIdEmployee() {
        return childrenByIdEmployee;
    }
 
    public void setChildrenByIdEmployee(Collection<ChildrenEntity> childrenByIdEmployee) {
        this.childrenByIdEmployee = childrenByIdEmployee;
    }
 
    @ManyToOne
    @JoinColumn(name = "id_PostAndDepartment", referencedColumnName = "id_PostAndDepartment")
    public PostanddepartmentEntity getPostanddepartmentByIdPostAndDepartment() {
        return postanddepartmentByIdPostAndDepartment;
    }
 
    public void setPostanddepartmentByIdPostAndDepartment(PostanddepartmentEntity postanddepartmentByIdPostAndDepartment) {
        this.postanddepartmentByIdPostAndDepartment = postanddepartmentByIdPostAndDepartment;
    }
}