Selector selector = Selector.open();channel.configureBlocking(false);SelectionKey key = channel.register(selector, SelectionKey.OP_READ);while(true) {  int readyChannels = selector.select();  if(readyChannels == 0) continue;  Set selectedKeys = selector.selectedKeys();  Iterator keyIterator = selectedKeys.iterator();  while(keyIterator.hasNext()) {    SelectionKey key = keyIterator.next();    if(key.isAcceptable()) {        // a connection was accepted by a ServerSocketChannel.    } else if (key.isConnectable()) {        // a connection was established with a remote server.    } else if (key.isReadable()) {        // a channel is ready for reading    } else if (key.isWritable()) {        // a channel is ready for writing    }    keyIterator.remove();  }}