The limit is ignored when calling this method on DBCollection:
getCount(DBObject query, DBObject fields, long limit, long skip, ReadPreference readPrefs). This will fix the issue, but not sure if this is intended behaviour or not:

< if ( limit > 0 )
< cmd.put( "limit" , limit );
< }

> if ( limit > 0 )

{ > cmd.put( "limit" , limit ); > cmd.put( "applySkipLimit", true ); > }