<class catalog="project" name="project.backend.hibernate.Users" table="users">
    <id name="username" type="string">
      <column length="50" name="username"/>
      <generator class="assigned"/>
    </id>
    <property name="password" type="string">
      <column length="50" name="password" not-null="true"/>
    </property>
    <property name="enabled" type="boolean">
      <column name="enabled" not-null="true"/>
    </property>

    <set inverse="true" name="userinformations">
      <key>
        <column length="50" name="username" not-null="true" unique="true"/>
      </key>
      <one-to-many class="project.backend.hibernate.Userinformation"/>
    </set>

  </class>

public class Users  implements java.io.Serializable {

     private String username;
     private String password;
     private boolean enabled;
     private Set userinformations = new HashSet(0);

    public Users() {
    }
   
    public Users(String username, String password, boolean enabled) {
        this.username = username;
        this.password = password;
        this.enabled = enabled;
    }
    public Users(String username, String password, boolean enabled, Set userinformations) {
       this.username = username;
       this.password = password;
       this.enabled = enabled;
       this.userinformations = userinformations;
    }
 
// more getter and setter

    public Set getUserinformations() {
        return this.userinformations;
    }
   
    public void setUserinformations(Set userinformations) {
        this.userinformations = userinformations;
    }

}

<class catalog="project" name="project.backend.hibernate.Userinformation" table="userinformation">
    <id name="email" type="string">
      <column length="50" name="email"/>
      <generator class="assigned"/>
    </id>
    <many-to-one class="project.backend.hibernate.Users" fetch="select" name="users">
      <column length="50" name="username" not-null="true" unique="true"/>
    </many-to-one>
// more properties, unimportant..
</class>

public class Userinformation  implements java.io.Serializable {

     private String email;
     private Users users;

    public Userinformation() {
    }

   
    public Userinformation(String email, Users users) {
        this.email = email;
        this.users = users;
    }

    public Userinformation(String email, Users users) {
   // here are more informations set, I reduced them because its shorter then but I dont really understand why there are so many constructors??
       this.email = email;
       this.users = users;
    }
   
    public String getEmail() {
        return this.email;
    }
   
    public void setEmail(String email) {
        this.email = email;
    }

  public Users getUsers() {
        return this.users;
    }
   
    public void setUsers(Users users) {
        this.users = users;
    }

// more, unimportant

}

public class HibernateDao {

    public Users loadUsersByUsername(String username) {
      return (Users) this.sessionFactory.getCurrentSession().get(Users.class, username);
    }
   
   public Users loadUsersByUsernameWithUserinformationJoin(String username) {
// seems to be wrong
        List<Users> list = this.sessionFactory.getCurrentSession()
                .createQuery("from Users users where users.username=? left join users.userinformation as userinformation")
                .setParameter(0, username)
                .list();
        Users u = list.get(0);
        return u;
    }

    public Userinformation loadUserinformationByUsers(Users u) {
        List<Userinformation> list = this.sessionFactory.getCurrentSession()
                .createQuery("from Userinformation userinformation where userinformation.users=?")
                .setParameter(0, u)
                .list();
        Userinformation userinf = list.get(0);
        return userinf;
    }


}

            // 1. Possibility:
            // load first Users object by username. Then load Userinformation by Users object. These are two database queries which does not look good to me.
            //Userinformation userinf2 = projectDao.loadUserinformationByUsers(projectDao.loadUsersByUsername(username));
           
            // 2. load a Users object by username. Then call getUserinformations from the users object which returns a set. But what then? I dont know how to work with that set?
            //Set set =  projectDao.loadUsersByUsername(username).getUserinformations();
            //Userinformation userinf =  .... ?

            /* 3. Possibility:
             * load a Users object by username. Then call getUserinformations from the users object which returns a set. Cast this set to a list to work with it. Unfortunately this does not work...
             * List<Userinformation> list = (List<Userinformation>) projectDao.loadUsersByUsername(username).getUserinformations();
            Userinformation userinf = list.get(0);
             */
     
            // 4. join
           // I read about using inner joins, left joins, outer joins... to get the collections with the object, but that is not working. ?!
           // the method I tried with is public Users loadUsersByUsernameWithUserinformationJoin(String username), this returns a users object. I tried to get then the userinformation from it, but it is still a set.
           

    public Userinformation loadUsersByUsernameWithUserinformation(String username) {
        Users u = (Users) this.sessionFactory.getCurrentSession().get(Users.class, username);
         Map userinf = (Map) u.getUserinformations();
         Userinformation userinfObject = (Userinformation) userinf;
         return userinfObject;
    }