Newly-developed encoding issue with an Oracle Java program

My Java program (or rather, a part of it) sends a request to a webservice and receives rdf-strings including ancient Greek words in unicode. I wrote the program in netbeans and so far, there has not been a problem during run-time, both in the netbeans environment and outside as a standalone jar under Linux and Windows XP. Now, all of a sudden the Greek words in the rdf come back garbled like this:

á¼€

At first, I thought this was a Windows XP problem, but when checking under Windows 7 the problem persisted. I found out that I was running OpenJDK under Linux, and was since able to reproduce the issue using Oracle Java. This is the relevant code (of course, I may have tunnel vision, so please tell me if you need more):

try {
        HttpClient client = new DefaultHttpClient();
        HttpGet get;
        get = new HttpGet(URL+URLEncoder.encode(form, "UTF-8"));

        HttpResponse response = client.execute(get);
        if (201 == response.getStatusLine().getStatusCode()) {
            HttpEntity respEnt = response.getEntity();
            BufferedReader reader = new BufferedReader(new InputStreamReader(respEnt.getContent()));
            StringBuilder sb = new StringBuilder();
            char[] cbuffer = new char[256];
            int read;

            while ((read = reader.read(cbuffer)) != -1) {
                sb.append(cbuffer,0,read);
            }
            //System.out.println(sb.toString());
            rdf = new String(sb.toString().getBytes("UTF-8"),"UTF-8");

        } else {
            System.err.println("HTTP Request fehlgeschlagen.");
        }         

    } catch (IOException e) {
        System.err.println("Problem beim HTTP Request.");
    }

The webservice is the Perseus morphology service, it can be found here: http://services.perseids.org/bsp/morphologyservice/analysis/word?lang=grc&engine=morpheusgrc&word=. Try "word=μῆνιν", for example. How or when the rdf is generated, I really don't know.

I would be very grateful for further insights!