为什么这段代码只能在带有断点的调试模式下工作？ （IDE调试器）

Question

你好我正在编写一个简单的telnet（后来即将有一个自定义的telnet客户端解释命令）命令和控制服务器在纯java 和我有一些代码，只有当我有调试器并在正确的地方断点这是奇怪

代码：

主营：

package LiteDoor; 

import java.io.File; 
import java.net.ServerSocket; 
import java.net.Socket; 
import java.util.ArrayList; 

import LiteDoor.net.AcceptTelnetClient; 

public class Main { 

    public static final String VERSION = "v0.0.1"; 

    public static File scripts = new File("scripts"); 

    public static ArrayList<AcceptTelnetClient> conns = new ArrayList<AcceptTelnetClient>(); 

    public static void main(String args[]) throws Exception 
    { 
     File autorun = new File(scripts.getAbsolutePath()+File.separatorChar+"autorun.litescript"); 
     if (!autorun.exists()) { 
      scripts.mkdirs(); 
      autorun.createNewFile(); 
     } 

     ServerSocket Soc=new ServerSocket(666); 
     while(true) 
     { 
      Socket CSoc=Soc.accept(); 
      AcceptTelnetClient ob=new AcceptTelnetClient(CSoc); 
     } 
    } 

} 

AcceptTelnetClient：

package LiteDoor.net; 

import java.io.BufferedReader; 
import java.io.File; 
import java.io.FileReader; 
import java.io.IOException; 
import java.io.InputStreamReader; 
import java.io.OutputStreamWriter; 
import java.net.Socket; 

import LiteDoor.Main; 
import LiteDoor.io.MyBufferedWriter; 

public class AcceptTelnetClient extends Thread { 
    Socket ClientSocket; 
    public boolean master; 
    public String slaveCmd = null; 

    public AcceptTelnetClient(Socket CSoc) throws Exception { 
     Main.conns.add(this); 

     ClientSocket=CSoc; 
     System.out.println("Client Connected ..."); 
     BufferedReader in = new BufferedReader(new InputStreamReader(ClientSocket.getInputStream())); 
     @SuppressWarnings("resource") 
     MyBufferedWriter out = new MyBufferedWriter(new OutputStreamWriter(ClientSocket.getOutputStream())); 

     out.writeln("MASTER/SLAVE?"); 

     switch(in.readLine().toUpperCase()) { 
     case("MASTER"): 
      master = true; 
      break; 
     case("SLAVE"): 
      master = false; 
      break; 
     } 

     int i=0; 
     while(i<200) { 
      out.newLine(); 
      i++; 
     } 
     out.flush(); 

     start();   
    } 

    public void run() { 
     try {  
      BufferedReader in=new BufferedReader(new InputStreamReader(ClientSocket.getInputStream())); 
      @SuppressWarnings("resource") 
      MyBufferedWriter out = new MyBufferedWriter(new OutputStreamWriter(ClientSocket.getOutputStream())); 

      out.writeln(""); 

      if (!master) { 
       BufferedReader fr = new BufferedReader(new FileReader(Main.scripts.getAbsolutePath()+File.separatorChar+"autorun.litescript")); 
       String line = fr.readLine(); 
       while(line != null) { 
        if (!line.startsWith("#") && line != "") { 
         out.writeln(line); 
        } 
        line = fr.readLine(); 
       } 
       fr.close(); 
      } 

      boolean loop = true; 

      while(loop) { 
       if (master) { 
        String cmd = in.readLine(); 
        if(cmd.startsWith("quit")) { 

         loop=false; 

        } else { 
         System.out.println("Master says: " + cmd); 
         for (AcceptTelnetClient con : Main.conns) { 
          if (!con.master) { 
           synchronized (con) { 
            con.slaveCmd = cmd; 
           } 
          } 
         } 
        } 
       } else { 
        if (slaveCmd != null) { 
         synchronized (this) { // Here needs to be an breakpoint 
          out.writeln(slaveCmd); 
          slaveCmd = null; 
         } 
        } 
       } 
      } 
      ClientSocket.close(); 
     } catch (IOException e) { 
      e.printStackTrace(); 
     } finally { 
      try { 
       ClientSocket.close(); 
      } catch (IOException e) { 
       e.printStackTrace(); 
      } 
     } 
    } 
} 

shloud发生什么：

客户端1连接到服务器类型的“奴隶” 并等待，直到一些命令得到sended它

客户端2在“主”连接类型并发送一些命令 是那么shloud得到sended到连接为“奴”

所有客户端会发生什么： 客户端1连接为从 客户端2连接的主机发送一个命令，但是奴隶不得到它（它不会在Telnet客户端窗口显示）

代码工作正常只有在调试器，并与断点正确的地方

PS是的，我试着用搜索引擎却一无所获

Answer 1

TL; DR ...

你不能肯定的是，正在运行的线程获取布尔标志主控的更新值，声明挥发性代替...

public volatile boolean master;