Hi Mark, one entry in my long list of self made problems is: "Done the commit before the ConcurrentUpdateSolrServer was finished."
Since the ConcurrentUpdateSolrServer is asynchronous, it's very easy to create a race conditions. Make sure that your program is waiting () before it's doing the commit.
if (solrserver instanceof ConcurrentUpdateSolrServer) { ((ConcurrentUpdateSolrServer) solrserver).blockUntilFinished(); }
Uwe