@Entity
public class Department {

    @Id
    @GeneratedValue
    private long id;

    private String name;

    @OneToMany(mappedBy = "department")
    private List<Person> persons;

    @OneToOne
    private DepartmentType type;

    @Override
    public String toString() {
        return "Department id=" + this.id + " " + this.name;
    }

    // region getters

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public List<Person> getPersons() {
        return persons;
    }

    public void setPersons(List<Person> persons) {
        this.persons = persons;
    }

    public DepartmentType getType() {
        return type;
    }

    public void setType(DepartmentType type) {
        this.type = type;
    }

    // endregion
}


@Entity
@NamedEntityGraph(name="departnemtsTypesWithDepartments", attributeNodes={@NamedAttributeNode("department")})
@NamedQuery(name = "departmetTypes",
            query = "select dt from DepartmentType dt where dt.id=:dtId",
            hints = @QueryHint(name=QueryHints.HINT_LOADGRAPH, value = "departnemtsTypesWithDepartments")
)
public class DepartmentType {

    @Id
    @GeneratedValue
    private Long id;

    private String name;

    @OneToOne(mappedBy="type")
    private Department department;

    //region getters

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public Department getDepartment() {
        return department;
    }

    public void setDepartment(Department department) {
        this.department = department;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    //endregion
}

public class Main {

   static EntityManagerFactory emf = Persistence.createEntityManagerFactory("default");

    public static void main(String[] args) {
        EntityManager em = emf.createEntityManager();
        em.getTransaction().begin();
        EntityGraph gr = em.getEntityGraph("departnemtsTypesWithDepartments");
        em.createQuery("select dt from DepartmentType dt", DepartmentType.class)
                .setHint(QueryHints.HINT_LOADGRAPH, gr)
                .getResultList().forEach(dt->{
                        System.out.println(dt);
                        System.out.println(dt.getDepartment());
        });

        em.getTransaction().commit();

    }
}

public class Main {

   static EntityManagerFactory emf = Persistence.createEntityManagerFactory("default");

    public static void main(String[] args) {
        EntityManager em = emf.createEntityManager();
        em.getTransaction().begin();
        em.createNamedQuery("departmetTypes", DepartmentType.class)
                .setParameter("dtId", 337L)
                .getResultList().forEach(dt->{
                    System.out.println(dt);
                    System.out.println(dt.getDepartment());
        });

        em.getTransaction().commit();

    }
}

@Target( { TYPE, PACKAGE })
@Retention(RUNTIME)
@Repeatable(NamedQueries.class)
public @interface NamedQuery {

	/**
	 * The name of this {@code NamedQuery}.
	 */
	String name();

	/**
	 * The query string for this {@code NamedQuery}.
	 */
	String query();

	/**
	 * The flush mode for this query.
	 */
	FlushModeType flushMode() default FlushModeType.PERSISTENCE_CONTEXT;

	/**
	 * Whether the query (results) is cacheable or not.  Default is {@code false}, that is not cacheable.
	 */
	boolean cacheable() default false;

	/**
	 * If the query results are cacheable, name the query cache region to use.
	 */
	String cacheRegion() default "";

	/**
	 * The number of rows fetched by the JDBC Driver per trip.
	 */
	int fetchSize() default -1;

	/**
	 * The query timeout (in seconds).  Default is no timeout.
	 */
	int timeout() default -1;

	/**
	 * A comment added to the generated SQL query.  Useful when engaging with DBA.
	 */
	String comment() default "";

	/**
	 * The cache mode used for this query.  This refers to entities/collections returned from the query.
	 */
	CacheModeType cacheMode() default CacheModeType.NORMAL;

	/**
	 * Whether the results should be read-only.  Default is {@code false}.
	 */
	boolean readOnly() default false;
}

@Target({TYPE})
@Retention(RUNTIME)
public @interface NamedQuery {

    /**
     * (Required) The name used to refer to the query with the {@link EntityManager}
     * methods that create query objects.
     */
    String name();

    /** (Required)
     * The query string in the Java Persistence query language.
     */
    String query();

    /**
     * (Optional) The lock mode type to use in query execution.  If a <code>lockMode</code>
     * other than <code>LockModeType.NONE</code> is specified, the query must be executed in
     * a transaction.
     * @since Java Persistence 2.0
     */
    LockModeType lockMode() default NONE;

    /** (Optional) Query properties and hints.  May include
     * vendor-specific query hints.
     */
    QueryHint[] hints() default {};
}