EntityManager entityManager;

public List<YourEntity> getEntitiesByParams(Map<Field1Class, Field2Class> params) {
    CriteriaBuilder cb = entityManager.getCriteriaBuilder();
    CriteriaQuery<YourEntity> query = cb.createQuery(YourEntity.class);
    Root<YourEntity> root = query.from(YourEntity.class);

    final List<Predicate> predicates = new ArrayList<>();
    for(Entry<Field1Class, Field2Class> entry : params.entrySet()) {
        Predicate predicate1 = cb.equal(root.get("field1"), params.getKey());
        Predicate predicate2 = cb.equal(root.get("field2"), params.getValue());

        predicates.add(
             cb.and(predicate1, predicate2)
        );
    }

    query.select(root)
         .where(
              cb.or(predicates.toArray(new Predicate[predicates.size()]))
         );

    return entityManager.createQuery(query).getResultList();
}