code: public Map<String, String[]> addParameterMap(Map<String, String[]> map) {
  
          if (map == null) {
              return m_parameters;
          }
          if ((m_parameters == null) || (m_parameters.size() == 0)) {
              m_parameters = Collections.unmodifiableMap(map);
          } else {
              Map<String, String[]> parameters = new HashMap<String, String[]>();
              parameters.putAll(m_parameters);
  
              Iterator<Map.Entry<String, String[]>> it = map.entrySet().iterator();
              while (it.hasNext()) {
                  Map.Entry<String, String[]> entry = it.next();
                  String key = entry.getKey();
                  // Check if the parameter name (key) exists
                  if (parameters.containsKey(key)) {
  
                      String[] oldValues = parameters.get(key);
                      String[] newValues = entry.getValue();
  
                      String[] mergeValues = new String[oldValues.length + newValues.length];
                      System.arraycopy(newValues, 0, mergeValues, 0, newValues.length);
                      System.arraycopy(oldValues, 0, mergeValues, newValues.length, oldValues.length);
  
                      parameters.put(key, mergeValues);
                  } else {
                      // No: Add new value array
                      parameters.put(key, entry.getValue());
                  }
              }
              m_parameters = Collections.unmodifiableMap(parameters);
          }
  
          return m_parameters;
      }
docs: Adds the specified Map to the parameters of the request,
  added parameters will not overwrite existing parameters in the
  request.<p>
  
  Remember that the value for a parameter name in
  a HttpRequest is a String array. If a parameter name already
  exists in the HttpRequest, the values will be added to the existing
  value array. Multiple occurrences of the same value for one
  parameter are also possible.<p>
  
  @param map the map to add
  
  @return the merged map of parameters