Content-Length header already present

I am using the Apache HttpClient (4.1) included in Android to execute a HttpPut. I have verified that I only have 1 content-length header. However, every time I send the request, I get a protocol exception about the Content-Length header already specified.

HttpClient client = new DefaultHttpClient();
putMethod = new HttpPut(url + encodedFileName);
putMethod.addHeader(..)  //<-once for each header
putMethod.setEntity(new ByteArrayEntity(data));
client.execute(putMethod);  //throws Exception

Caused by: org.apache.http.ProtocolException: Content-Length header already present at org.apache.http.protocol.RequestContent.process(RequestContent.java:70) at org.apache.http.protocol.BasicHttpProcessor.process(BasicHttpProcessor.java:290)

Any ideas?

Answer

I’ve not used HttpClient myself, but I suspect that the problem is that putMethod.setEntity(...) is implicitly supplying a content length and you are also setting it explicitly via one of the putMethod.addHeader(...) calls.