lt;Long, String, Person&gt; personByEmployerIds;
  Employer employer = ...;

  // Match on all Person objects having parentSsn "111-11-1111" and also
  // containing an employerId of employer.id.  In other words, match on all
  // of Bob's children that work for a given employer.
  //
  EntityJoin&lt;String, Person&gt; join = new EntityJoin(personBySsn);
  join.addCondition(personByParentSsn, "111-11-1111");
  join.addCondition(personByEmployerIds, employer.id);

  // Perform the join operation by traversin