"message": "could not execute statement; nested exception is org.hibernate.exception.GenericJDBCException: could not execute statement",

whenever I try to add something into my table documents using the userId as a parameter I get this error message in postman using this "localhost:9293/SpringMVC/servlet/documents/add?userId=2"

could not execute statement; nested exception is org.hibernate.exception.GenericJDBCException: could not execute statement

I already have a user created with the userId=2

my user.java

@Entity(name="user")
public class User implements Serializable , UserDetails  {

/**
 * 
 */
private static final long serialVersionUID = 1L;

private User user;

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private int userId;
private String name;
private int phone_number;
private String email;
private String password;
private String address;
private boolean verified;
private boolean subscribed;
private String idStrype;
//@Column(nullable = true, length = 64)
//private String documents;

@ManyToOne(cascade = CascadeType.PERSIST, fetch = FetchType.LAZY)
@JsonIgnore
@JsonBackReference
private Role role;


@OneToMany(cascade = CascadeType.PERSIST,mappedBy="user",fetch=FetchType.LAZY)
//@JsonManagedReference
private Set<Ad> ads;

@OneToOne(cascade = CascadeType.ALL, mappedBy = "user")
private Documents documents;


/*@OneToMany(cascade = CascadeType.PERSIST,mappedBy="user",fetch=FetchType.LAZY)
//@JsonManagedReference
private Set<Insurance> insurances;*/

@OneToMany(cascade = CascadeType.PERSIST,mappedBy="user",fetch=FetchType.LAZY)
//@JsonManagedReference
private Set<Offer> offers;


@OneToMany(cascade = CascadeType.PERSIST,mappedBy="user",fetch=FetchType.LAZY)
//@JsonManagedReference
private Set<Contract> contracts;


@OneToMany(cascade = CascadeType.PERSIST,mappedBy="user",fetch=FetchType.LAZY)
//@JsonManagedReference
private Set<Reclamation> reclamations;





public String getIdStrype() {
    return idStrype;
}

public void setIdStrype(String idStrype) {
    this.idStrype = idStrype;
}

/**
 * @return the userId
 */
public int getUserId() {
    return userId;
}

/**
 * @param userId the userId to set
 */
public void setUserId(int userId) {
    this.userId = userId;
}

/**
 * @return the name
 */
public String getName() {
    return name;
}

/**
 * @param name the name to set
 */
public void setName(String name) {
    this.name = name;
}

/**
 * @return the phone_number
 */
public int getPhone_number() {
    return phone_number;
}

/**
 * @param phone_number the phone_number to set
 */
public void setPhone_number(int phone_number) {
    this.phone_number = phone_number;
}

/**
 * @return the email
 */
public String getEmail() {
    return email;
}

/**
 * @param email the email to set
 */
public void setEmail(String email) {
    this.email = email;
}

my documents.java

@Entity
@Table(name= "document")
public class Documents implements Serializable {

private static final long serialVersionUID = 1L;


@Id
@GeneratedValue(strategy= GenerationType.IDENTITY)
@Column(name= "id")
private int id;


@Column(name="fichedepaie")
private String fichedepaie;

@Column(name="piecedidentite")
private String piecedidentite;

@Column(name="lettredengagement")
private String lettredengagement;

@Column(name="cautionnement")
private String cautionnement;

@OneToOne
private User user;


public int getId() {
    return id;
}

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

public String getFichedepaie() {
    return fichedepaie;
}

public void setFichedepaie(String fichedepaie) {
    this.fichedepaie = fichedepaie;
}

public String getPiecedidentite() {
    return piecedidentite;
}

public void setPiecedidentite(String piecedidentite) {
    this.piecedidentite = piecedidentite;
}

public String getLettredengagement() {
    return lettredengagement;
}

public void setLettredengagement(String lettredengagement) {
    this.lettredengagement = lettredengagement;
}

public String getCautionnement() {
    return cautionnement;
}

public void setCautionnement(String cautionnement) {
    this.cautionnement = cautionnement;
}

public User getUser() {
    return user;
}

public void setUser(User user) {
    this.user = user;
}

public Documents(String fichedepaie, String piecedidentite, String lettredengagement, String cautionnement) {
    super();
    this.fichedepaie = fichedepaie;
    this.piecedidentite = piecedidentite;
    this.lettredengagement = lettredengagement;
    this.cautionnement = cautionnement;
}


public Documents() {
    super();
}

}

my documentsService.java

@Override
public Documents addDocuments(Documents d, int userid) {
    // TODO Auto-generated method stub
    d.setUser(userrepo.findById(userid).get());
    docrepo.save(d);
    return d;
}

my documentsController.java

@RestController
@RequestMapping("/documents")
public class DocumentsController {

@Autowired
DocumentsService docserv ;

@Autowired
UserRepository userrepo;

@PostMapping("/add")
private Documents addDocuments(@RequestBody Documents docs, @RequestParam("userId") int userId)   
{  
    docserv.addDocuments(docs,userId);  
    return docs;  
}