JPA User, Role, manyToMany hibernate relationship

Question

I'm using JPA+Hibernate+SpringBoot+PostgreSQL, to create a relationship between different entities, but I am getting a ton of errors, including what looks like SQL errors, but the application started up anyway. Did I code the manyToMany relation correctly? There could be many users, and each user can have multiple roles. Maybe OneToMany is better?

I'm using "spring-boot-starter-data-jpa"

These are the only hibernate files I have so far.

Role.java

@Entity(name = "role")
public class Role implements java.io.Serializable {
    /**
     * 
     */
    private static final long serialVersionUID = -5525359165179861924L;
    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    @Column(name = "id")
    int id;

    private String role;

    @ManyToMany(mappedBy = "roles",fetch = FetchType.LAZY)
    private Set<User> users;


    public Role(String role) {
        super();
        this.role = role;
    }

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

    public int getId(){
        return id;
    }

    public String getRole() {
        return role;
    }

    public void setRole(String role) {
        this.role = role;
    }

    public Set<User> getUsers() {
        return users;
    }

    public void setUser(Set<User> users) {
        this.users = users;
    }
}

User.java

@Entity
@Table(name = "user")
public class User implements java.io.Serializable {

    private static final long serialVersionUID = 4910225916550731448L;

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "id", unique = true, nullable = false)
    private Long id;

    @Column(name = "created")
    Date created;

    @Column(name = "firstName", length = 100)
    private String firstName;

    @Column(name = "lastName", length = 100)
    private String lastName;

    @Column(name = "email", length = 150)
    private String email;

    @Column(name = "username", length = 150)
    private String username;

    @Column(name = "enabled")
    private int enabled;

    @ManyToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL)
    @JoinTable(joinColumns = @JoinColumn(name = "userId", referencedColumnName = "id"), 
    inverseJoinColumns = @JoinColumn(name = "roleId", referencedColumnName = "id"))
    private Set<Role> roles;

    protected User(){
        roles = new HashSet<Role>();
    }

    public Set<Role> getRoles(){
        return roles;
    }

    public void setRoles(Set<Role> roles){
        this.roles = roles;
    }

    public User(String firstName, String lastName, String email, String username, Set<Role> roles) {
        this.firstName = firstName;
        this.lastName = lastName;
        this.email = email;
        this.username = username;
        this.roles = roles;
    }
}

And the errors I get:

2017-04-24 22:49:19.163  WARN 20488 --- [  restartedMain] org.hibernate.orm.deprecation            : HHH90000014: Found use of deprecated [org.hibernate.id.SequenceGenerator] sequence-based id generator; use org.hibernate.id.enhanced.SequenceStyleGenerator instead.  See Hibernate Domain Model Mapping Guide for details.
2017-04-24 22:49:19.167  WARN 20488 --- [  restartedMain] org.hibernate.orm.deprecation            : HHH90000014: Found use of deprecated [org.hibernate.id.SequenceGenerator] sequence-based id generator; use org.hibernate.id.enhanced.SequenceStyleGenerator instead.  See Hibernate Domain Model Mapping Guide for details.
2017-04-24 22:49:19.438  INFO 20488 --- [  restartedMain] org.hibernate.tuple.PojoInstantiator     : HHH000182: No default (no-argument) constructor for class: com.example.domain.Role (class must be instantiated by Interceptor)
2017-04-24 22:49:19.527  INFO 20488 --- [  restartedMain] org.hibernate.tool.hbm2ddl.SchemaExport  : HHH000227: Running hbm2ddl schema export
Hibernate: alter table user_roles drop constraint FKrhfovtciq1l558cw6udg0h0d3
2017-04-24 22:49:19.531 ERROR 20488 --- [  restartedMain] org.hibernate.tool.hbm2ddl.SchemaExport  : HHH000389: Unsuccessful: alter table user_roles drop constraint FKrhfovtciq1l558cw6udg0h0d3
2017-04-24 22:49:19.531 ERROR 20488 --- [  restartedMain] org.hibernate.tool.hbm2ddl.SchemaExport  : ERROR: relation "user_roles" does not exist
Hibernate: alter table user_roles drop constraint FK55itppkw3i07do3h7qoclqd4k
2017-04-24 22:49:19.532 ERROR 20488 --- [  restartedMain] org.hibernate.tool.hbm2ddl.SchemaExport  : HHH000389: Unsuccessful: alter table user_roles drop constraint FK55itppkw3i07do3h7qoclqd4k
2017-04-24 22:49:19.533 ERROR 20488 --- [  restartedMain] org.hibernate.tool.hbm2ddl.SchemaExport  : ERROR: relation "user_roles" does not exist
Hibernate: drop table if exists role cascade
Hibernate: drop table if exists user cascade
2017-04-24 22:49:19.535 ERROR 20488 --- [  restartedMain] org.hibernate.tool.hbm2ddl.SchemaExport  : HHH000389: Unsuccessful: drop table if exists user cascade
2017-04-24 22:49:19.535 ERROR 20488 --- [  restartedMain] org.hibernate.tool.hbm2ddl.SchemaExport  : ERROR: syntax error at or near "user"
  Position: 22
Hibernate: drop table if exists user_roles cascade
Hibernate: drop sequence hibernate_sequence
2017-04-24 22:49:19.537 ERROR 20488 --- [  restartedMain] org.hibernate.tool.hbm2ddl.SchemaExport  : HHH000389: Unsuccessful: drop sequence hibernate_sequence
2017-04-24 22:49:19.538 ERROR 20488 --- [  restartedMain] org.hibernate.tool.hbm2ddl.SchemaExport  : ERROR: sequence "hibernate_sequence" does not exist
Hibernate: create sequence hibernate_sequence start 1 increment 1
Hibernate: create table role (id int4 not null, role varchar(255), primary key (id))
Hibernate: create table user (id int8 not null, created timestamp, email varchar(150), enabled int4, first_name varchar(100), last_name varchar(100), username varchar(150), primary key (id))
2017-04-24 22:49:19.564 ERROR 20488 --- [  restartedMain] org.hibernate.tool.hbm2ddl.SchemaExport  : HHH000389: Unsuccessful: create table user (id int8 not null, created timestamp, email varchar(150), enabled int4, first_name varchar(100), last_name varchar(100), username varchar(150), primary key (id))
2017-04-24 22:49:19.564 ERROR 20488 --- [  restartedMain] org.hibernate.tool.hbm2ddl.SchemaExport  : ERROR: syntax error at or near "user"
  Position: 14
Hibernate: create table user_roles (user_id int8 not null, role_id int4 not null, primary key (user_id, role_id))
Hibernate: alter table user_roles add constraint FKrhfovtciq1l558cw6udg0h0d3 foreign key (role_id) references role
Hibernate: alter table user_roles add constraint FK55itppkw3i07do3h7qoclqd4k foreign key (user_id) references user
2017-04-24 22:49:19.585 ERROR 20488 --- [  restartedMain] org.hibernate.tool.hbm2ddl.SchemaExport  : HHH000389: Unsuccessful: alter table user_roles add constraint FK55itppkw3i07do3h7qoclqd4k foreign key (user_id) references user
2017-04-24 22:49:19.585 ERROR 20488 --- [  restartedMain] org.hibernate.tool.hbm2ddl.SchemaExport  : ERROR: syntax error at or near "user"
  Position: 100
2017-04-24 22:49:19.585  INFO 20488 --- [  restartedMain] org.hibernate.tool.hbm2ddl.SchemaExport  : HHH000230: Schema export complete

Solution

First of all you should drop your database or change your hibernate config to create

<prop key="hibernate.hbm2ddl.auto">create</prop>

and the error is

ERROR: relation "user_roles" does not exist

so you should name the ManyToMany as user_roles:

@JoinTable(name="user_roles",
        joinColumns = {@JoinColumn(name="user_id", referencedColumnName="id")},
        inverseJoinColumns = {@JoinColumn(name="role_id", referencedColumnName="id")}
    )
    private List<Role> roles;

in My project User Entity is :

  @Entity
@Table(name = "user")
public class User extends AbstractPersistable<Long>{


    private static final long serialVersionUID = 1L;


    @Column(name = "USER_NAME", unique = true)
    private String username;
    @Column(name = "PASSWORD")
    private String password;



    @ManyToMany(cascade=CascadeType.ALL,fetch=FetchType.EAGER)
    @JoinTable(name="user_roles",
        joinColumns = {@JoinColumn(name="user_id", referencedColumnName="id")},
        inverseJoinColumns = {@JoinColumn(name="role_id", referencedColumnName="id")}
    )
    private List<Role> roles;



    public String getUsername() {
        return username;
    }



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



    public String getPassword() {
        return password;
    }



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



    public List<Role> getRoles() {
        return roles;
    }



    public void setRoles(List<Role> roles) {
        this.roles = roles;
    }



    public User(String username, String password, List<Role> roles) {
        super();
        this.username = username;
        this.password = password;
        this.roles = roles;
    }



    public User() {
        super();
    }
}

and Roles :

 @Entity
@Table(name = "roles")
public class Role extends AbstractPersistable<Long> {

    private static final long serialVersionUID = 1L;

    private String role;

    public String getRole() {
        return role;
    }

    public void setRole(String role) {
        this.role = role;
    }

    public Role() {
    }

    public Role(String role) {
        this.role = role;
    }

}