code: public static void decodeAndAppendEntries(Map<String, String> source,
                                                Map<String, String> target) {
          for (Entry<String, String> entry : source.entrySet()) {
              target.put(URLUtils.percentEncode(entry.getKey()),
                      URLUtils.percentEncode(entry.getValue()));
          }
      }
docs: Form-urlDecodes and appends all keys from the source {@link Map} to the
  target {@link Map}
  
  @param source Map from where the keys get copied and decoded
  @param target Map where the decoded keys are copied to