Cookie empty value copy

should be:

protected void copyRequestHeaders(HttpServletRequest servletRequest,
HttpRequest proxyRequest) {
// Get an Enumeration of all of the header names sent by the client
Enumeration enumerationOfHeaderNames = servletRequest.getHeaderNames();
while (enumerationOfHeaderNames.hasMoreElements()) {
String headerName = (String) enumerationOfHeaderNames.nextElement();
// Instead the content-length is effectively set via
// InputStreamEntity
if (headerName.equalsIgnoreCase(HttpHeaders.CONTENT_LENGTH))
continue;
if (hopByHopHeaders.containsHeader(headerName))
continue;

        Enumeration headers = servletRequest.getHeaders(headerName);
        while (headers.hasMoreElements()) {// sometimes more than one value
            String headerValue = (String) headers.nextElement();
            // In case the proxy host is running multiple virtual servers,
            // rewrite the Host header to ensure that we get content from
            // the correct virtual server
            if (headerName.equalsIgnoreCase(HttpHeaders.HOST)) {
                HttpHost host = getTargetHost(servletRequest);
                headerValue = host.getHostName();
                if (host.getPort() != -1)
                    headerValue += ":" + host.getPort();
            } else if (headerName
                    .equalsIgnoreCase(org.apache.http.cookie.SM.COOKIE)) {
                    headerValue = getRealCookie(headerValue);
            }
            if (headerValue != null && !headerValue.equals("")) {
                proxyRequest.addHeader(headerName, headerValue);
            }
        }
    }
}

to avoid "Cookie: "

example: with Grizzly Server as target after proxy will couse in target 500 error, bcs of sending "Cookie: "

Locate the copyRequestHeaders(HttpServletRequest, HttpRequest) method shown in the issue and inspect how cookie headers are transformed before being added to the proxy request. Reproduce the Grizzly target failure if possible, then verify that an empty cookie value is not forwarded and that normal cookie values still are.