jpa entity relation many to many self relation

I wish to make jpa entity for clients, something like adding friends on facebook or googe+ Got a bit confused

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package entities;

import java.util.List;
import javax.persistence.Basic;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
import javax.persistence.Table;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlTransient;

 * @author nikola
@Table(name = "Client")
    @NamedQuery(name = "Client.findAll", query = "SELECT c FROM Client c"),
    @NamedQuery(name = "Client.findByClientId", query = "SELECT c FROM Client c WHERE c.clientId = :clientId"),
    @NamedQuery(name = "Client.findByClientName", query = "SELECT c FROM Client c WHERE c.clientName = :clientName")})
public class Client implements Serializable {
    private static final long serialVersionUID = 1L;
    @Basic(optional = false)
    @Column(name = "ClientId")
    private Integer clientId;
    @Size(max = 45)
    @Column(name = "ClientName")
    private String clientName;
    @JoinTable(name = "Friends", joinColumns = {
        @JoinColumn(name = "Client_ClientId", referencedColumnName = "ClientId")}, inverseJoinColumns = {
        @JoinColumn(name = "Client_ClientId1", referencedColumnName = "ClientId")})
    private List<Client> clientList;
    @ManyToMany(mappedBy = "clientList")
    private List<Client> clientList1;

    public Client() {

    public Client(Integer clientId) {
        this.clientId = clientId;

    public Integer getClientId() {
        return clientId;

    public void setClientId(Integer clientId) {
        this.clientId = clientId;

    public String getClientName() {
        return clientName;

    public void setClientName(String clientName) {
        this.clientName = clientName;

    public List<Client> getClientList() {
        return clientList;

    public void setClientList(List<Client> clientList) {
        this.clientList = clientList;

    public List<Client> getClientList1() {
        return clientList1;

    public void setClientList1(List<Client> clientList1) {
        this.clientList1 = clientList1;

    public int hashCode() {
        int hash = 0;
        hash += (clientId != null ? clientId.hashCode() : 0);
        return hash;

    public boolean equals(Object object) {
        // TODO: Warning - this method won't work in the case the id fields are not set
        if (!(object instanceof Client)) {
            return false;
        Client other = (Client) object;
        if ((this.clientId == null && other.clientId != null) || (this.clientId != null && !this.clientId.equals(other.clientId))) {
            return false;
        return true;

    public String toString() {
        return "entities.Client[ clientId=" + clientId + " ]";


I have clientList and clientList1, do not know which one to use when i wish to add a client to my list of friends. Thanks for any advice.


The good practice is to update both, to keep the object graph in a consistent state:

Client mainClient = ...;
Client newFriend = ...;

But the owner of the association, which is the only side that JPA considers, is the one which does not have the mappedBy attribute. So you could add a new friendship to the database by only adding a client to clientList.

For better readability, I would choose better names for the lists. Something like clientsWhoAreFriendsOfMe, and clientsWhoChoseMeAsFriend.

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