java get browser type

public String getBrowserType(HttpServletRequest request)
  {
    String type = "ie";
    String browserName = request.getHeader("USER-AGENT").toLowerCase();

    if (browserName.indexOf("msie") > 0) {
      type = "ie";
    }

    if (browserName.indexOf("firefox") > 0) {
      type = "firefox";
    }

    if (browserName.indexOf("chrome") > 0) {
      type = "chrome";
    }

    if (browserName.indexOf("opera") > 0) {
      type = "opera";
    }
    if(browserName.indexOf("gecko")>0 && browserName.indexOf("rv:11")>0){
      type="ie11";
    }

    return type;
  }