code: public void setHeader(String name, String value) {
  		if (headers == null) {
  			headers = new HashMap<String, String>();
  		}
  		if (value != null) {
  			headers.put(name, value);
  		} else {
  			headers.remove(name);
  		}
  	}
docs: Set HTTP header value or remove named header if <code>value</code> is null.
  
  @param name HTTP header name,
  @param value HTTP header value, possible null.
  @since 1.9