带有插座的readyLine和readLine之间的区别

Question

我试图将服务器置于“等待模式”，但是当我使用以下语法时：

new Thread() {
        public void run() {       
            BufferedReader in;
            String op;
            try {
                in = new BufferedReader(new InputStreamReader(incoming.getInputStream()));
                while ((op = in.readLine()) != null) {
                    if (op.equals("Elimina")) {
                        String tmp = in.readLine();
                        File file = new File("src/server/" + nomeAccount + "/" + tmp + ".txt");
                        file.delete();
                    }
                }
            } catch (IOException ex) {
                System.out.println("Unable to read messages");
            } finally {
                try {
                    incoming.close();
                } catch (IOException ex) {
                    System.out.println("Cannot close the socket");
                }
            }
        }
    }.start();

该程序卡在while ((op = in.readLine()) != null)上，并且客户端从不加载其GUI（如果不加载，我将无法进行任何输入）。因此，我决定使用以下语法：

new Thread() {
            @Override
            public void run() {       
                BufferedReader in;
                String op;
                try {
                    in = new BufferedReader(new InputStreamReader(incoming.getInputStream()));
                    while (in.ready()) {
                        op = in.readLine();
                        if (op.equals("Elimina")) {
                            String tmp = in.readLine();
                            contenutoTextArea.append("Ho eliminato la mail " + tmp + " \n");
                            textarea.setText(contenutoTextArea.toString());
                            File file = new File("src/server/" + nomeAccount + "/" + tmp + ".txt");
                            file.delete();
                        }
                    }
                    System.out.println("bbbbb");
                } catch (IOException ex) {
                    System.out.println("Unable to read messages");
                } finally {
                    try {
                        incoming.close();
                    } catch (IOException ex) {
                        System.out.println("Cannot close the socket");
                    }
                }
            }
        }.start();

现在的问题是该程序永远不会进入循环。在此之前，我尝试使用while (true)，但程序再次卡住。