@Entity
@Table(name = "userEntity", schema = "public")
public class UsersEntity implements java.io.Serializable{
    private Integer userId;
    private String name;
    private Integer date;
    private String username;
    private String phone;
    private String email;
    private String password;
    private String country;
    private Set<Stock> stock = new HashSet<Stock>(
            0);

    public UsersEntity() {
    }

    public UsersEntity(Integer userId, String name, Integer date, String username,
                       String phone, String email, String password, String country,
                       Set<Stock> stock) {
        this.userId = userId;
        this.name = name;
        this.date = date;
        this.username = username;
        this.phone = phone;
        this.email = email;
        this.password = password;
        this.country = country;
        this.stock = stock;
    }

    @Column(name = "name", nullable = true, length = 255)
    public String getName() {
        return name;
    }

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

    @Id
    @Column(name = "userId")
    @GeneratedValue(strategy = GenerationType.IDENTITY, generator = "user_seq_gen")
    @SequenceGenerator(name = "user_seq_gen", sequenceName = "user_id_seq")
    public Integer getUserId() {
        return userId;
    }

    public void setUserId(Integer userId) {
        this.userId = userId;
    }

    @Column(name = "date", nullable = true, length = 255)
    public Integer getDate() {
        return date;
    }

    public void setDate(Integer date) {
        this.date = date;
    }

    @Column(name = "username", nullable = true, length = 255)
    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    @Column(name = "phone", nullable = true, length = 255)
    public String getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone;
    }

    @Column(name = "email", nullable = true, length = 255)
    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    @Column(name = "password", nullable = true, length = 255)
    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    @Column(name = "country", nullable = true, length = 255)
    public String getCountry() {
        return country;
    }

    public void setCountry(String country) {
        this.country = country;
    }

    @OneToMany(fetch = FetchType.LAZY, mappedBy = "userEntity")
    public Set<Stock> getStock() {
        return this.stock;
    }

    public void setStock(Set<Stock> stock) {
        this.stock = stock;
    }

@Entity
@Table(name = "stock", schema = "public")
public class Stock {
    private int id;
    private String description;
    private UsersEntity usersEntity;

    public Stock() {
    }

    public Stock(int id, String description) {
        this.id = id;
        this.description = description;
    }

    @Id
    @GeneratedValue(strategy = IDENTITY)
    @Column(name = "id", unique = true, nullable = false)
    public int getId() {
        return id;
    }

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

    @Column(nullable = true, length = 255)
    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "userId", nullable = false)
    public UsersEntity getUser() {
        return this.usersEntity;
    }

    public void setUser(UsersEntity usersEntity) {
        this.usersEntity = usersEntity;
    }

<hibernate-configuration>
    <session-factory>
        <property name="hbm2ddl.auto">create</property>
        <property name="connection.url">jdbc:postgresql://localhost:5432/personal2</property>
        <property name="connection.username">postgres</property>
        <property name="connection.password">root</property>
        <property name="connection.driver_class">org.postgresql.Driver</property>

        <mapping class="Entity.UsersEntity"/>
        <mapping class="Entity.Stock"/>

org.hibernate.AnnotationException: mappedBy reference an unknown target entity property: Entity.Stock.userEntity in Entity.UsersEntity.stock