Does the TopDocsCollector sort the docs it returns?
The java doc for...
public final TopDocs topDocs(int start)
Returns the documents in the range [start .. pq.size()) that were collected by this collector. Note that if start >= pq.size(), an empty TopDocs is returned.
This method is convenient to call if the application always asks for the last results, starting from the last 'page'.
So it returns the proper results for a given page, but it is not clear that it sorts the results for that page.
I would have thought it does sort the results for the returned docs, but I'm seeing some results that show that the results are not sorted.