How does javax.persistence.criteria.CriteriaBuilder#or work? - spring-boot

Question

I've created a custom repository to filter a list of entities from the db. Below is a basic initialization of the implemented class (entities are reduced to letters for clarification):
#Repository
public class CustomXRepositoryImpl implements CustomXRepository {
private final EntityManager em;
private final CriteriaBuilder builder;
private final CriteriaQuery<X> query;
private final Root<X> root;
#Autowired
public CustomXRepositoryImpl(EntityManager em) {
this.em = em;
builder = em.getCriteriaBuilder();
query = builder.createQuery(X.class);
root = query.from(X.class);
}
}
and the method I implemented:
#Override
public List<X> filter(FilterParams params) {
List<Predicate> restrictions = new ArrayList<>();
// some if-statements ...
if (params.getY() != null) {
Expression<?> path1 = root.get("a").get("b").get("y");
Expression<?> path2 = root.get("c").get("d").get("y");
Predicate p1 = builder.equal(path1, params.getY());
Predicate p2 = builder.equal(path2, params.getY());
// restrictions.add(p1); // 3 results for Y = 4
// restrictions.add(p2); // no result for Y = 4
restrictions.add(builder.or(p1, p2)); // no result
}
// more if-statements ...
query.where(restrictions.toArray(new Predicate[0]));
return em.createQuery(query).getResultList();
}
What makes me confused is the fact that builder.or(p1, p2) returns no result, even though p1 is satisfied. I also find the CriteriaBuilder#or documentation (Returns a disjunction of the given restriction predicates) very ambiguous.
Can anyone explain this behavior?