code: public boolean validation() throws ParallelTaskInvalidException {
  
          if (this.getAsyncHttpClient() == null) {
              logger.info("USE DEFAULT HTTP CLIENT: Did not set special asyncHttpClient, will use the current default one: "
                      + HttpClientStore.getInstance()
                              .getHttpClientTypeCurrentDefault().toString());
              this.asyncHttpClient = HttpClientStore.getInstance()
                      .getCurrentDefaultClient();
          }
          
          if (this.getHttpMethod() == null)
              throw new ParallelTaskInvalidException("Missing getHttpMethod!");
          if (this.getHeaderMetadata() == null) {
              logger.info("USE DEFAULT EMPTY HEADER: Did not specify HTTP header. Will use empty header."
                      + " Use .setHeaders to add headers");
              this.setHeaderMetadata(new ParallecHeader());
          }
          // if null it is OK, just set as the default
          if (this.getEntityBody() == null)
                                 setEntityBody(PcConstants.COMMAND_VAR_DEFAULT_REQUEST_CONTENT);
  
          if (this.getRequestPort() == null) {
              setRequestPort("80");
              logger.info("USE DEFAULT PORT: Missing port. SET default port to be 80");
          }
  
          if (this.getRequestUrlPostfix() == null
                  || this.getRequestUrlPostfix().trim().isEmpty()) {
              setRequestUrlPostfix("");
              logger.info("USE DEFAULT URL: RequestUrlPostfix is null or empty. SET as empty \"\". e.g. just want to GET http://parallec.io");
          }
          if (this.isPollable() &&
                  this.getHttpPollerProcessor() == null) {
                  throw new ParallelTaskInvalidException(
                          "set pollable but httpPollerProcessor is null!! Invalid. please set httpPollerProcessor() ");
          }
  
          return true;
  
      }
docs: Validation.
  
  @return true, if successful
  @throws ParallelTaskInvalidException
  the parallel task invalid exception