spring - Check if User object exists in @DBRef List<User> -

i'm making use of mongodb, spring data , spring mvc. have user model has list of contacts:

class user { @dbref private list<user> contacts = new arraylist<user>();   public list<user> getcontacts() {     return contacts; } } 

i have 4 users inside database. 1 user has particular contact (who referred same collection id).

now, want check whether user has particular contact. use following code:

user userloggedin = userservice.getloggedinuser(); //user object user contact = userservice.findbyid(contactid); //contact if(userloggedin.getcontacts().contains(contact)) {     system.out.println("has contact."); } 

this output message not shown. however, if print list of contacts of user , id's, see contact inserted inside list of user.

i noticed if print hashcode of contact object , 1 inside list, different value, assume though details same, object isn't.

how can approach problem checking whether inside list. or should compare id?

otherwise stated: how can check whether object exists in contacts list?

you should override equals method in user.

from javadoc:

boolean contains(object o)

returns true if list contains specified element. more formally, returns true if , if list contains @ least 1 element e such (o==null ? e==null : o.equals(e)).

with equals must override , hashcode

http://docs.jboss.org/hibernate/core/4.0/manual/en-us/html/persistent-classes.html#persistent-classes-equalshashcode