public SetIfModifiedSince() throws Exception { serverSock = new ServerSocket(0); int port = serverSock.getLocalPort(); Thread thr = new Thread(this); thr.start(); Date date = new Date(new Date().getTime() - 1440000); // this time yesterday URL url; HttpURLConnection con; // url = new URL(args[0]); url = new URL("http://localhost:" + String.valueOf(port) + "/anything"); con = (HttpURLConnection) url.openConnection(); con.setIfModifiedSince(date.getTime()); con.connect(); int ret = con.getResponseCode(); if (ret == 304) { System.out.println("Success!"); } else { throw new RuntimeException( "Test failed! Http return code using setIfModified method is:" + ret + "\nNOTE:some web servers are not implemented according to RFC, thus a failed test does not necessarily indicate a bug in setIfModifiedSince method"); } }