Today I found something very interesting. When i search a word (solr; lucene) ending with a semicolon plus any character (from solr admin page), solr gives an exception (HTTP Status 400 - Missing sort order). When I escaped semicolon (solr\;lucene) exception gone.
I checked Lucene Special Characters that are part of the query syntax. Semicolon (;) is not in the list. I wanted to share this with you.