Improved: SeoContextFilter.java is not able to handle query strings

(OFBIZ-11278)

Removes a trailing blank and uses empty to check request::getParameterMap result

Thanks: Mathieu to spot "empty to check request::getParameterMap result"

applications/product/src/main/java/org/apache/ofbiz/product/category/SeoContextFilter.java

@@ -101,15 +101,15 @@ public void doFilter(ServletRequest request, ServletResponse response, FilterCha
         String uri = httpRequest.getRequestURI();
 
         Map<String, String[]> parameterMap =request.getParameterMap();
-        if (parameterMap != null) {
+        if (!parameterMap.isEmpty()) {
             List<BasicNameValuePair> params = new ArrayList<BasicNameValuePair>();
             request.getParameterMap().forEach((name, values) -> {
                 for(String value : values) {
                     params.add(new BasicNameValuePair(name, value));
                 }
             });
             String queryString = URLEncodedUtils.format(params, Charset.forName("UTF-8"));
-            uri = uri + "?" + queryString; 
+            uri = uri + "?" + queryString;
         }
 
         boolean forwarded = forwardUri(httpResponse, uri);