code: public UriComponentsBuilder queryParam(String name, Object... values) {
  		Assert.notNull(name, "'name' must not be null");
  		if (!ObjectUtils.isEmpty(values)) {
  			for (Object value : values) {
  				String valueAsString = (value != null ? value.toString() : null);
  				this.queryParams.add(name, valueAsString);
  			}
  		}
  		else {
  			this.queryParams.add(name, null);
  		}
  		resetSchemeSpecificPart();
  		return this;
  	}
docs: Append the given query parameter to the existing query parameters. The
  given name or any of the values may contain URI template variables. If no
  values are given, the resulting URI will contain the query parameter name
  only (i.e. {@code ?foo} instead of {@code ?foo=bar}.
  @param name the query parameter name
  @param values the query parameter values
  @return this UriComponentsBuilder