code: public void setRequestBody(NameValuePair[] parametersBody)
      throws IllegalArgumentException {
          log.trace("enter PostMethod.setRequestBody(NameValuePair[])");
  
          if (parametersBody == null) {
              throw new IllegalArgumentException("Array of parameters may not be null");
          }
          clearRequestBody();
          addParameters(parametersBody);
      }
docs: Sets an array of parameters to be used in the POST request body
  
  @param parametersBody The array of parameters to add.
  
  @throws IllegalArgumentException when param parameters are null
  
  @since 2.0beta1