Update the document field with solrj


I want to edit document filed in solr,for example edit the author name,so i use the following code in solrj:


but the author multivalued="true" in schema and because of that "anaconde" is not replace with it's previous name and add to the end of the author name,also if i ommit the multivalued field or set it to false the bad request exception happen in re-indexing file with new author field,how can i solve this problem and delete or modify the previous document field in solrj? or does it any config i miss in schema? thanks

The only option I know of would be to query the full document (all fields using &fl=* parameter) into a local construct with solrj, update the appropriate field(s) and them submit the entire document back to Solr.