Me too, and that's not correct. Firstly, the idea that NIO is "not much harder to use at all (compared to io streams)" is wild on its own. People built Netty (

Me too, and that's not correct. Firstly, the idea that NIO is "not much harder to use at all (compared to io streams)" is wild on its own. People built Netty (and XNIO) precisely because of how awkward NIO is to use. But secondly, there are common, useful patterns that are trivial with streams and extremely awkward with asynchronous I/O. For example, here's some code which queries a database and streams the results to the client as JSON: OutputStream responseBody; // assume you get this from somewhere try (JsonGenerator json = Json.createGenerator(responseBody)) { json.writeStartArray(); try (Connection connection = openDatabaseConnection()) { ResultSet results = connection.prepareStatement("select first_name, last_name from users").executeQuery(); while (results.next()) { json.writeStartObject(); json.write("first_name", results.getString("first_name")); json.write("last_name", results.getString("last_name")); json.writeEnd(); } } json.writeEnd(); } It does not load all the data into memory, it does not buffer all the JSON in memory, it automatically handles backpressure (if the socket blocks on a write, it will pause reading results from the database), it releases its resources cleanly if an exception occurs, and it's fourteen lines of very simple code. You cannot do anything like this with an asynchronous API.