Ошибка при сохранении объекта в базу данных Oracle

У меня есть две таблицы USER_ и ORDER_. Создал классы:

@Entity
@Table(name = "USER_")
public class User {
    private long id;
    private String userName;
    private String password;
    private String country;
    private String userType;
    private List<Order> orders;
    public User() {
    }
    public User(String userName, String password, String country, String userType) {
        this.userName = userName;
        this.password = password;
        this.country = country;
        this.userType = userType;
    }
    public User(String userName, String password, String country, String userType, List<Order> orders) {
        this.userName = userName;
        this.password = password;
        this.country = country;
        this.userType = userType;
        this.orders = orders;
    }
    @Id
    @SequenceGenerator(name = "US_SQ", sequenceName = "USER_SEQ", allocationSize = 1)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "US_SQ")
    @Column(name = "ID")
    public long getId() {
        return id;
    }
    @Column(name = "USER_NAME")
    public String getUserName() {
        return userName;
    }
    @Column(name = "PASSWORD")
    public String getPassword() {
        return password;
    }
    @Column(name = "COUNTRY")
    public String getCountry() {
        return country;
    }
    @Column(name = "USER_TYPE")
    public String getUserType() {
        return userType;
    }
    @OneToMany(targetEntity = Order.class, mappedBy = "user", fetch = FetchType.LAZY)
    public List<Order> getOrders() {
        return orders;
    }

и

@Entity
@Table(name = "ORDER_")
public class Order {
    private long id;
    private User user;
    private Room room;
    private Date dateFrom;
    private Date dateTo;
    private double moneyPaid;
    public Order() {
    }
    @Id
    @SequenceGenerator(name = "ORDER_SQ", sequenceName = "ORDER_SEQ", allocationSize = 1)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "ORDER_SQ")
    @Column(name = "ID")
    public long getId() {
        return id;
    }
    @ManyToOne
    @JoinColumn(name = "ID_USER")
    public User getUser() {
        return user;
    }
    @OneToOne(optional = false, cascade = CascadeType.ALL)
    @JoinColumn(name = "ID_ROOM")
    public Room getRoom() {
        return room;
    }
    @Temporal(TemporalType.DATE)
    @Column(name = "DATE_FROM")
    public Date getDateFrom() {
        return dateFrom;
    }
    @Temporal(TemporalType.DATE)
    @Column(name = "DATE_TO")
    public Date getDateTo() {
        return dateTo;
    }
    @Column(name = "MONEY_PAID")
    public double getMoneyPaid() {
        return moneyPaid;
    }

Так же есть класс GeneralDAO<T> в котором метод сохранения объекта в базу, не привожу его здесь, так как он вполне рабочий. В Demo создаю объект user и сохраняю его в базу userGeneralDAO.save(user1); и тут падает ошибка:

"C:\Program Files\Java\jdk1.8.0_111\bin\java" "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA Community Edition 2018.1\lib\idea_rt.jar=57967:C:\Program Files\JetBrains\IntelliJ IDEA Community Edition 2018.1\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_111\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\rt.jar;C:\Users\Skorodielov\IdeaProjects\javajdbcgrom\target\classes;C:\Users\Skorodielov\.m2\repository\com\oracle\ojdbc7\12.1.0\ojdbc7-12.1.0.jar;C:\Users\Skorodielov\.m2\repository\org\hibernate\hibernate-core\5.2.16.Final\hibernate-core-5.2.16.Final.jar;C:\Users\Skorodielov\.m2\repository\org\jboss\logging\jboss-logging\3.3.1.Final\jboss-logging-3.3.1.Final.jar;C:\Users\Skorodielov\.m2\repository\org\hibernate\javax\persistence\hibernate-jpa-2.1-api\1.0.0.Final\hibernate-jpa-2.1-api-1.0.0.Final.jar;C:\Users\Skorodielov\.m2\repository\org\javassist\javassist\3.22.0-GA\javassist-3.22.0-GA.jar;C:\Users\Skorodielov\.m2\repository\antlr\antlr\2.7.7\antlr-2.7.7.jar;C:\Users\Skorodielov\.m2\repository\org\jboss\spec\javax\transaction\jboss-transaction-api_1.2_spec\1.0.1.Final\jboss-transaction-api_1.2_spec-1.0.1.Final.jar;C:\Users\Skorodielov\.m2\repository\org\jboss\jandex\2.0.3.Final\jandex-2.0.3.Final.jar;C:\Users\Skorodielov\.m2\repository\com\fasterxml\classmate\1.3.0\classmate-1.3.0.jar;C:\Users\Skorodielov\.m2\repository\dom4j\dom4j\1.6.1\dom4j-1.6.1.jar;C:\Users\Skorodielov\.m2\repository\org\hibernate\common\hibernate-commons-annotations\5.0.1.Final\hibernate-commons-annotations-5.0.1.Final.jar" hibernate_dz.dz_lesson4.demo.UserDemo
мая 18, 2018 10:23:04 AM org.hibernate.Version logVersion
INFO: HHH000412: Hibernate Core {5.2.16.Final}
мая 18, 2018 10:23:04 AM org.hibernate.cfg.Environment <clinit>
INFO: HHH000206: hibernate.properties not found
мая 18, 2018 10:23:04 AM org.hibernate.boot.jaxb.internal.stax.LocalXmlResourceResolver resolveEntity
WARN: HHH90000012: Recognized obsolete hibernate namespace http://hibernate.sourceforge.net/hibernate-configuration. Use namespace http://www.hibernate.org/dtd/hibernate-configuration instead.  Support for obsolete DTD/XSD namespaces may be removed at any time.
мая 18, 2018 10:23:05 AM org.hibernate.annotations.common.reflection.java.JavaReflectionManager <clinit>
INFO: HCANN000001: Hibernate Commons Annotations {5.0.1.Final}
мая 18, 2018 10:23:05 AM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
WARN: HHH10001002: Using Hibernate built-in connection pool (not for production use!)
мая 18, 2018 10:23:05 AM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001005: using driver [oracle.jdbc.driver.OracleDriver] at URL [jdbc:oracle:thin:@gromcode-lesson.cjqbbseqr63c.eu-central-1.rds.amazonaws.com:1521:ORCL]
мая 18, 2018 10:23:05 AM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001001: Connection properties: {user=main, password=****}
мая 18, 2018 10:23:05 AM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001003: Autocommit mode: false
мая 18, 2018 10:23:05 AM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl$PooledConnections <init>
INFO: HHH000115: Hibernate connection pool size: 20 (min=1)
мая 18, 2018 10:23:07 AM org.hibernate.dialect.Dialect <init>
INFO: HHH000400: Using dialect: org.hibernate.dialect.Oracle10gDialect
Save is failed
Collection has neither generic type or OneToMany.targetEntity() defined: hibernate_dz.dz_lesson4.model.Hotel.rooms
Process finished with exit code -1

Подскажите как её исправить ? И в аннотации OneToMany параметр mappedBy = должно быть название таблицы или наименование колонки, которая является внешним ключом для связи таблиц USER_ и ORDER_ ?