SolrJ Collapsable Query Fails

[Kurt Sultana]

I am currently trying to run a collapsable query using SolrJ using SolR 3.3.
The problem is that when I run the query through the web interface, with
this url:

http://localhost:8080/solr/select/?q=attr_content%3Alynx&sort=attr_location+desc&group=true&group.field=attr_directory

I am able to see the XML which is returned. The problem though, is that when
I try to run the same query through SolrJ, using this code:

        SolrQuery queryString = new SolrQuery();

        for (String param : query.keySet())

        {
            if (param.equals("fq"))

            {
                queryString.addFilterQuery(query.get(param));

            }
            else
            {
                queryString.setParam(param, query.get(param));

            }
        }

        System.out.println(queryString.toString());

        QueryResponse response = server.query(queryString);
//Exception takes place at this line

        SolrDocumentList docList = response.getResults();

Which constructs a URL like so:

q=attr_content%3Alynx&sort=attr_location+desc&group=true&group.field=attr_directory

This throws an exception:

Caused by: org.apache.solr.common.SolrException: parsing error at
org.apache.solr.client.solrj.impl.XMLResponseParser.processResponse(XMLResponseParser.java:145)
at
org.apache.solr.client.solrj.impl.XMLResponseParser.processResponse(XMLResponseParser.java:106)
at
org.apache.solr.client.solrj.impl.CommonsHttpSolrServer.request(CommonsHttpSolrServer.java:477)
at
org.apache.solr.client.solrj.impl.CommonsHttpSolrServer.request(CommonsHttpSolrServer.java:244)
at
org.apache.solr.client.solrj.request.QueryRequest.process(QueryRequest.java:89)
... 3 more Caused by: javax.xml.stream.XMLStreamException: ParseError at
[row,col]:[3,30088] Message: error reading value:LST at
org.apache.solr.client.solrj.impl.XMLResponseParser.readArray(XMLResponseParser.java:324)
at
org.apache.solr.client.solrj.impl.XMLResponseParser.readNamedList(XMLResponseParser.java:245)
at
org.apache.solr.client.solrj.impl.XMLResponseParser.readNamedList(XMLResponseParser.java:244)
at
org.apache.solr.client.solrj.impl.XMLResponseParser.readNamedList(XMLResponseParser.java:244)
at
org.apache.solr.client.solrj.impl.XMLResponseParser.processResponse(XMLResponseParser.java:130)

I have tried it with both Jetty and Tomcat, the error is the same for both.
I have managed to get other queries to run (with both servers), so I presume
that the problem lies with this particular type of query.

Any insight on this problem will be highly appreciated,

Thanks :)