web/play-java-forms/src/main/java/play/data/validation/Constraints.java
public static List<Tuple<String, List<Object>>> displayableConstraint(
      Set<ConstraintDescriptor<?>> constraints) {
    return constraints
        .parallelStream()
        .filter(c -> c.getAnnotation().annotationType().isAnnotationPresent(Display.class))
        .map(c -> displayableConstraint(c))
        .collect(Collectors.toList());
  }
public static List<Tuple<String, List<Object>>> displayableConstraint(
      Set<ConstraintDescriptor<?>> constraints) {
    return constraints
        .parallelStream()
        .filter(c -> c.getAnnotation().annotationType().isAnnotationPresent(Display.class))
        .map(c -> displayableConstraint(c))
        .collect(Collectors.toList());
  }
Converts a set of constraints to human-readable values. Does not guarantee the order of the
returned constraints.

<p>This method calls {@code displayableConstraint} under the hood.

@param constraints the set of constraint descriptors.
@return a list of pairs of tuples assembled from displayableConstraint.