for (int i = 0; i < 2500; i++) {
	Query q = em.createQuery("from Department dep where dep.name = :name");
	q.setParameter("name", "dep_" + i);
	Department dep = (Department) q.getSingleResult();
	System.out.println(dep.getName());
	
	Set<Employee> employees = dep.getEmployees();
	for (Employee employee : employees) {
		//
	}
}