public byte[] getResponseBody() throws IOException {
        if (this.responseBody == null) {
            InputStream instream = getResponseBodyAsStream();
            if (instream != null) {
                long contentLength = getResponseContentLength();
                if (contentLength > Integer.MAX_VALUE) { //guard below cast from overflow
                    throw new IOException("Content too large to be buffered: "+ contentLength +" bytes");
                }
                int limit = getParams().getIntParameter(HttpMethodParams.BUFFER_WARN_TRIGGER_LIMIT, 1024*1024);
                if ((contentLength == -1) || (contentLength > limit)) {
                    LOG.warn("Going to buffer response body of large or unknown size. "
                            +"Using getResponseBodyAsStream instead is recommended.");
                }
                LOG.debug("Buffering response body");
                ByteArrayOutputStream outstream = new ByteArrayOutputStream(
                        contentLength > 0 ? (int) contentLength : DEFAULT_INITIAL_BUFFER_SIZE);
                byte[] buffer = new byte[4096];
                int len;
                while ((len = instream.read(buffer)) > 0) {
                    outstream.write(buffer, 0, len);
                }
                outstream.close();
                setResponseStream(null);
                this.responseBody = outstream.toByteArray();
            }
        }
        return this.responseBody;
    }