java - JPA Self Referencing Entities -

i have table called user this:

public class user {     private long userid;     private string username;     //other fields; } 

now lets user can have other user friends. how create relationship in jpa.

meanwhile doing in user table in database:

user_id  username user_friends 

and in user entity this:

public class user {     private long userid;     private string username;     //other fields;     @onetomany(cascade = cascadetype.all)     @column(name = "user_friends")     private list<userentity> friends; } 

this doesn't work. so, how achieve in jpa? in advance!

after doing research , @florian schaetz, found solution self referencing entities. need user can have other user friends , user can friend other users. so, did this:

public class user {     private long userid;     private string username;     //other fields;     @jointable(name = "user_friends", joincolumns = {     @joincolumn(name = "adding_user", referencedcolumnname = "user_id", nullable =   false)}, inversejoincolumns = {     @joincolumn(name = "added_user", referencedcolumnname = "user_id", nullable = false)})     @manytomany     private collection<user> friends;      @manytomany(mappedby = "friends")     private collection<user> adduser; } 

hope other people! again friends!