Java 为什么我的计算机的状态是'；当我的手机调制解调器正在使用时，它的COM4端口可用吗？

这是我的密码：

import java.io.*;
import java.util.*;
import javax.comm.*;

public class SMS {


    public static void main(String[] args) {
            Enumeration lists=CommPortIdentifier.getPortIdentifiers();
            System.out.println(CommPortIdentifier.PORT_SERIAL);
            System.out.println(lists.hasMoreElements());
            while (lists.hasMoreElements()){
                CommPortIdentifier cn=(CommPortIdentifier)lists.nextElement();

                if ((CommPortIdentifier.PORT_SERIAL==cn.getPortType())){
                    System.out.println("Name is serail port "+cn.getName()+" Owned status "+cn.isCurrentlyOwned());

                    try{
                        SerialPort port1=(SerialPort)cn.open("ComControl",800000);
                        port1.setSerialPortParams(9600, SerialPort.DATABITS_8, SerialPort.STOPBITS_1, SerialPort.PARITY_NONE);
                        System.out.println("Before get stream");
                        OutputStream out=port1.getOutputStream();
                        InputStream input=port1.getInputStream();
                        System.out.println("Before write");
                        out.write("AT".getBytes());
                        System.out.println("After write");
                        int sample=0;
                        //while((( sample=input.read())!=-1)){
                        System.out.println("Before read");
                            //System.out.println(input.read() + "Testing ");
                        //}
                            System.out.println("After read");
                        System.out.println("Receive timeout is "+port1.getReceiveTimeout());
                    }catch(Exception e){
                        System.err.println(e.getMessage());
                    }
                }

                else{
                    System.out.println("Name is parallel port "+cn.getName()+" Owned status "+cn.isCurrentlyOwned()+cn.getPortType()+"    ");
                }
            }
    }

}

这是输出：

1 true Name is serail port COM1 Owned status false Before get stream Before write After write Before read After read Receive timeout is -1 Name is serail port COM2 Owned status false Before get stream Before write After write Before read After read Receive timeout is -1 Name is serail port COM3 Owned status false Before get stream Before write After write Before read After read Receive timeout is -1 Name is serail port COM4 Owned status false Before get stream Before write After write Before read After read Receive timeout is -1 Name is parallel port LPT1 Owned status false2 Name is parallel port LPT2 Owned status false2 1. 真的 名称为serail端口COM1拥有状态false 在得到流之前 写之前 写完后 阅读前 读完 接收超时为-1 名称为serail端口COM2所有状态为false 在得到流之前 写之前 写完后 阅读前 读完 接收超时为-1 名称为serail端口COM3所有状态为false 在得到流之前 写之前 写完后 阅读前 读完 接收超时为-1 名称为serail端口COM4拥有状态为false 在得到流之前 写之前 写完后 阅读前 读完 接收超时为-1 名称为并行端口LPT1拥有状态2 名称为并口LPT2所有状态2 我的手机调制解调器正在使用我的COM4端口，但根据代码，它的状态是免费的。

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代码中是否有我遗漏的内容？我如何才能将其整理出来？

可能是控制手机的软件处于睡眠模式，或者类似的情况