### Question:
AdvancedFilterableSupport implements AdvancedFilterable,
        Serializable { public Collection<Object> getFilterablePropertyIds() { if (filterablePropertyIds == null) { return Collections.emptyList(); } else { return Collections.unmodifiableCollection(filterablePropertyIds); } }  void addListener(ApplyFiltersListener listener); void removeListener(ApplyFiltersListener listener); Collection<Object> getFilterablePropertyIds(); @SuppressWarnings("unchecked") void setFilterablePropertyIds(Collection<?> propertyIds); void setFilterablePropertyIds(Object... propertyIds); boolean isFilterable(Object propertyId); boolean isValidFilter(Filter filter); List<Filter> getFilters(); List<Filter> getAppliedFilters(); void setApplyFiltersImmediately(boolean applyFiltersImmediately); boolean isApplyFiltersImmediately(); void applyFilters(); boolean hasUnappliedFilters(); @SuppressWarnings("unchecked") static Path<String> getPropertyPath(From<?, ?> root,
            Object propertyId); static Path<X> getPropertyPathTyped(From<X, Y> root,
            Object propertyId); void addFilter(Filter filter); void removeFilter(Filter filter); void removeAllFilters();  }### Answer:
@Test public void testFilterablePropertyIds_Unmodifiable() { try { testObject.getFilterablePropertyIds().add("hello"); fail("No exception thrown"); } catch (Exception e) { assertTrue(testObject.getFilterablePropertyIds().isEmpty()); } }