@BeforeClass public static void setup() { Spark.setPort(PORT); Spark.before( new Filter() { @Override public void handle(Request request, Response response) { response.header("FOZ", "BAZ"); } }); Books.main(null); Spark.after( new Filter() { @Override public void handle(Request request, Response response) { response.header("FOO", "BAR"); } }); try { Thread.sleep(500); } catch (Exception e) { } }