There is a difference in the way Facet results are reported in SolrJ from the REST interface. In REST, if you apply a facet via the fq param, no matter what the count it is always reported back in the list of facets in the responses. However, with SolrJ - it only reports back facets that don't match the total number of documents. This is quite frustrating to deal with.
The difference can be seen when ORing or ANDing in the fq param. When I or to facet values together, they come back in SolrJ since their counts don't match the total docs. But if I AND them together, they don't appear in the list. So then I need to munge in the applied fq values.
Why the difference in behavior between REST and SolrJ?