@Override public Map<String, String> getResponseHeaders() { Map<String, String> responseHeaders = new HashMap<String, String>(3); long lastModified = info.getLastModified(); responseHeaders.put("Last-Modified", Utils.formatRFC1123(new Date(lastModified))); responseHeaders.put( "Expires", Utils.formatRFC1123(new Date(System.currentTimeMillis() + info.getMaxAge()))); responseHeaders.put( "Etag", String.format("W/\"%d-%d\"", info.getContentLength(), lastModified)); responseHeaders.put( "Pragma", ""); // Explicitly set empty pragma to prevent some containers from setting it. return responseHeaders; }