code: @Override
  	public String resolveVariant(HttpServletRequest request) {
  
  		String browser = null;
  		String userAgent = request.getHeader("User-Agent");
  		if (userAgent != null) {
  			Matcher matcher = IE_PATTERN.matcher(userAgent);
  			if (matcher.find()) {
  				browser = "ie" + matcher.group(1);
  			} else if (userAgent.contains("AppleWebKit")) {
  				browser = "webkit";
  			} else if (userAgent.contains("Firefox")) {
  				browser = "firefox";
  			} else if (userAgent.contains("Opera")) {
  				browser = "opera";
  			}
  		}
  
  		return browser;
  	}
docs: /*
  (non-Javadoc)
  
  @see
  net.jawr.web.resource.bundle.variant.VariantResolver#resolveVariant(javax
  .servlet.http.HttpServletRequest)