Java 如何确保程序在正常关闭或崩溃时关闭套接字？

代码如下：

public static void main(String[] args) {
    SocketWorker worker = null;
    MyIOConsole  mio = null;

    try {
        portNumber = 2012;

        worker = new SocketWorker();    
        worker.assignPort(portNumber);

        mio = new MyIOConsole();
        mio.assignObject(worker);

        Thread b = new Thread(mio); 
        b.start();

        worker.run();

    } catch (IOException e) {
        e.printStackTrace();
    }finally{
        mio.applicationQuit();
    }
}

SocketWorker只是一个套接字，监听端口2012，MyIOConsole将接受用户命令

public class MyConsoleIO implements Runnable {

    SocketWorker o;
    static BufferedReader reader;

    public void assignObject(Object o) {

        reader = new BufferedReader(new InputStreamReader(System.in));

        this.o = (SocketWorker) o;

    }

    @Override
    public void run() {
        String inputString = null;

        System.out.println("Press 'q' to kill to program");
        try {
            inputString = reader.readLine();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        if (inputString.equalsIgnoreCase("q")) {
            this.applicationQuit();
        }
    }

    public void applicationQuit(){
        this.o.stopWorking();
        System.exit(0);
    }

}

但是当套接字出现异常时，即使我捕捉到它们，代码

        mio.applicationQuit();

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继续跑。我不希望这样，我只希望当用户关闭或崩溃应用程序时，套接字将关闭并退出。如何解决它？

添加以下内容。JVM退出时将调用run方法

Runtime.getRuntime().addShutdownHook(new Thread() {
    public void run(){
        // cleanup code before JVM exit goes here.
    }
});

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请添加SocketWorker代码以澄清问题