10.6.8 to 10.8.2 on mac mini no longer needed as a server

I have a ML capable mac mini server that I don't use as a server right now, it's basically a family machine with multiple users. I just turned off the server features under 10.6.8--now I am forced to move to the "cloud" I have MBP and imac that are running 10.8.2. I downloaded ML to the mini server, but if I am not going to use the server features, to I need to bother downloading os x server to put on top of it, or can I simply run it without the ML server download added?

Glad to have clarified things, I you do want to experiment though, it's nice to know that the new server application is no more expensive than 30 dollars - a huge contrast compared to Snow Leopard Server.

Similar Messages

A problem with threads

I am trying to implement some kind of a server listening for requests. The listener part of the app, is a daemon thread that listens for connections and instantiates a handling daemon thread once it gets some. However, my problem is that i must be able to kill the listening thread at the user's will (say via a sto button). I have done this via the Sun's proposed way, by testing a boolean flag in the loop, which is set to false when i wish to kill the thread. The problem with this thing is the following...
Once the thread starts excecuting, it will test the flag, find it true and enter the loop. At some point it will LOCK on the server socket waiting for connection. Unless some client actually connects, it will keep on listening indefinatelly whithought ever bothering to check for the flag again (no matter how many times you set the damn thing to false).
My question is this: Is there any real, non-theoretical, applied way to stop thread in java safely?
Thank you in advance,
Lefty

This was one solution from the socket programming forum, have you tried this??
public Thread MyThread extends Thread{
     boolean active = true;
     public void run(){
          ss.setSoTimeout(90);
          while (active){
               try{
                    serverSocket = ss.accept();
               catch (SocketTimeoutException ste){
               // do nothing
     // interrupt thread
     public void deactivate(){
          active = false;
          // you gotta sleep for a time longer than the
          // accept() timeout to make sure that timeout is finished.
          try{
               sleep(91);
          }catch (InterruptedException ie){
          interrupt();
}

Understanding problem with threads

Hi,
yesterday (at least i think it was yesterday) I posted a question in this forum, I needed help with writing a multithreaded server. The answer was simple and I wrote my program. It kinda works, but there is one thing I don't understand:
I have a class, which handles the clientconnections and one that listens for incoming conections. I pass the socket returned by ServerSocket.accept() to the clientconnection object.
There is only ONE clientconnection-object. The listener just passes the socket and calls the start() method of the clientconnection object.
The clientconnection just writes some text to the client. Connecting more than one client at the same time works too. Everything works fine. And that's what I don't get. If I have only O N E clientconnection the texttransfer shouldn't work after i connect the second client, right?
But it does, is there a mistake in my logic or am I losing my sanity? :)

Hi again Danbas,
Maybe you are losing your sanity... but that's ok. :)
public void startlistening(){
while(true){
try{
clientconn cc = new clientconn(ssock.accept());
}catch(IOException ie){}
//The Constructor in clientconn would look like this:
public clientconn(Socket sock){
//No idea what to do here
Every time you perform "new", you create a new object. And you are calling new every time you accept a new socket connection. So you are creating a new clientconn object each time.

A problem with Threads and loops.

Hi, I have some code that needs to be constantly running, like while(true)
      //code here
}However, the code just checks to see if the user has input anything (and then if the user has, it goes to do some other stuff) so I don't need it constantly running and hogging up 98% of the CPU. So I made my class (which has the method that needs to be looped, call it ClassA) implement Runnable. Then I just added the method which needed to be looped into the public void run()
I have another class which creates an instance of the above class (call it ClassB), and the main(String[] args) is in there.
public static void main(String[] args)
          ClassA test = new ClassA();
          Thread thread = new Thread(test.getInstanceOfClassA());
          thread.start();
          while(true)
                       //I do not know what to put here
               try
                    thread.sleep(100);
               catch(InterruptedException iex)
     }However, the thread only calls run() once,(duh...) but I can't think of away to get it to run - sleep - run -sleep forever. Can someone help me?

Hi, I have some code that needs to be constantly
running, like while(true)
//code here
}However, the code just checks to see if the user has
input anything (and then if the user has, it goes to
do some other stuff) so I don't need it constantly
running and hogging up 98% of the CPU. Where does the user input come from. Are you reading from an InputStream? If so, then your loop will be blocked anyway when reading from the InputStream until data is available. During that time, the loop will not consume processor cycles.
public static void main(String[] args)
          ClassA test = new ClassA();
Thread thread = new Thread(test.getInstanceOfClassA());I have never seen this idiom. If ClassA instanceof Runnable, you simply write new Thread(test).
          thread.start();
          while(true)
//I do not know what to put
do not know what to put here
               try
                    thread.sleep(100);
               catch(InterruptedException iex)
     }However, the thread only calls run() once,(duh...)Yeah, why would you want to call it more than once given that you have an infinite loop in ClassA.run()?
Harald.
Java Text Crunching: http://www.ebi.ac.uk/Rebholz-srv/whatizit/software

A problem with Threads and MMapi

I am tring to execute a class based on Game canvas.
The problem begin when I try to Play both a MIDI tone and to run an infinit Thread loop.
The MIDI tone "Stammers".
How to over come the problem?
Thanks in advance
Kobi
See Code example below:
import java.io.IOException;
import java.io.InputStream;
import javax.microedition.lcdui.Graphics;
import javax.microedition.lcdui.Image;
import javax.microedition.lcdui.game.GameCanvas;
import javax.microedition.media.Manager;
import javax.microedition.media.MediaException;
import javax.microedition.media.Player;
public class MainScreenCanvas extends GameCanvas implements Runnable {
     private MainMIDlet parent;
     private boolean mTrucking = false;
     Image imgBackgound = null;
     int imgBackgoundX = 0, imgBackgoundY = 0;
     Player player;
     public MainScreenCanvas(MainMIDlet parent)
          super(true);
          this.parent = parent;
          try
               imgBackgound = Image.createImage("/images/area03_bkg0.png");
               imgBackgoundX = this.getWidth() - imgBackgound.getWidth();
               imgBackgoundY = this.getHeight() - imgBackgound.getHeight();
          catch(Exception e)
               System.out.println(e.getMessage());
      * starts thread
     public void start()
          mTrucking = true;
          Thread t = new Thread(this);
          t.start();
      * stops thread
     public void stop()
          mTrucking = false;
     public void play()
          try
               InputStream is = getClass().getResourceAsStream("/sounds/scale.mid");
               player = Manager.createPlayer(is, "audio/midi");
               player.setLoopCount(-1);
               player.prefetch();
               player.start();
          catch(Exception e)
               System.out.println(e.getMessage());
     public void run()
          Graphics g = getGraphics();
          play();
          while (true)
               tick();
               input();
               render(g);
      * responsible for object movements
     private void tick()
      * response to key input
     private void input()
          int keyStates = getKeyStates();
          if ((keyStates & LEFT_PRESSED) != 0)
               imgBackgoundX++;
               if (imgBackgoundX > 0)
                    imgBackgoundX = 0;
          if ((keyStates & RIGHT_PRESSED) != 0)
               imgBackgoundX--;
               if (imgBackgoundX < this.getWidth() - imgBackgound.getWidth())
                    imgBackgoundX = this.getWidth() - imgBackgound.getWidth();
      * Responsible for the drawing
      * @param g
     private void render(Graphics g)
          g.drawImage(imgBackgound, imgBackgoundX, imgBackgoundY, Graphics.TOP | Graphics.LEFT);
          this.flushGraphics();
}

You can also try to provide a greater Priority to your player thread so that it gains the CPU time when ever it needs it and don't harm the playback.
However a loop in a Thread and that to an infinite loop is one kind of very bad programming, 'cuz the loop eats up most of your CPU time which in turn adds up more delays of the execution of other tasks (just as in your case it is the playback). By witting codes bit efficiently and planning out the architectural execution flow of the app before start writing the code helps solve these kind of issues.
You can go through [this simple tutorial|http://oreilly.com/catalog/expjava/excerpt/index.html] about Basics of Java and Threads to know more about threads.
Regds,
SD
N.B. And yes there are more articles and tutorials available but much of them targets the Java SE / EE, but if you want to read them here is [another great one straight from SUN|http://java.sun.com/docs/books/tutorial/essential/concurrency/index.html] .
Edited by: find_suvro@SDN on 7 Nov, 2008 12:00 PM

J2ME problem with threads

Hi all,
I would like to ask you for a help. I need to write a small program at my university. I started to write a midlet which function would be to countdown time for sports activities. I woul like to start a new thread - the one that counts down - and at the same time make the main thread sleep. After the "countdown" thread finishes, the main thread wakes up and waits for user input. The problem is that when the "countdown" thread finishes his work, I've got Uncaught exception java/lang/NullPointerException. error and the midlet halts.
Below you can find the code
import java.lang.*;
import java.util.*;
import javax.microedition.lcdui.*;
import javax.microedition.midlet.*;
public class intervals extends MIDlet implements CommandListener
public Display ekran;
private SweepCanvas sweeper;
private Form rundy;
private TextField round0, round1, round2, round3, round4, round5, round6, round7, round8;
private long czas,x;
private Command exitCommand;
private Command addRound;
private Command delRound;
private Command start;
private TextField repeat;
private Form odliczanie;
private Alert ostrz;
Licznik thread;
String test;
StringItem test1;
int parz,i,j,k;
static int l;
int ilrund;
int ilpowt;
Item sec;
long sec1;
public intervals()
    rundy = new Form("Interwały sportowe");
    exitCommand = new Command("Wyjście", Command.EXIT, 2);
    addRound = new Command("Dodaj","Dodaj rundę", Command.ITEM,1);
    delRound = new Command("Usuń","Usuń ostatnią rundę", Command.ITEM,1);
    start = new Command("Start", Command.ITEM,1);
    odliczanie = new Form("Odliczanie");
    TextField dodaj(TextField kolej)
        kolej=new TextField("Podaj czas (s) rundy "+parz,null, 4, TextField.NUMERIC);//stworzenie nowej instancji do wybierania czasu trwania rundy
        if(rundy.size()==0)
            rundy.insert(rundy.size(),kolej);
            else
                rundy.insert(rundy.size()-1, kolej);
        return kolej;
    void odliczanie(TextField round)
        monitor m=new monitor();
        k=Integer.parseInt(round.getString());
        ekran.setCurrent(odliczanie);
        thread=new Licznik(k,odliczanie);
        thread.start();
        ekran.setCurrent(rundy);
public void startApp()// throws MIDletStateChangeException
    rundy.deleteAll();
    repeat = new TextField("Podaj ilość powtórzeń",null,1,TextField.NUMERIC);
    rundy.addCommand(addRound);
    rundy.addCommand(exitCommand);
    rundy.setCommandListener(this);
    Canvas obrazek = new MyCanvas();
    ekran = Display.getDisplay(this);
    ekran.setCurrent(obrazek);
    czas=System.currentTimeMillis();
    while (System.currentTimeMillis()<czas+1000)
        continue;
    ekran.setCurrent(rundy);
public void pauseApp()
public void destroyApp(boolean unconditional)
    notifyDestroyed();
public void commandAction(Command c, Displayable s)
    if (c == exitCommand)
        destroyApp(false);
        notifyDestroyed();
    else if(c==addRound)
        if(rundy.size()==0)//Sprawdzenie ilości elementów w celu poprawnego wyświetlania liczby rund w formie
            parz=1;
            else
            parz=rundy.size();
        switch(parz)
            case 1:
                round0=dodaj(round0);break;
            case 2:
                round1=dodaj(round1);break;
            case 3:
               round2= dodaj(round2);break;
            case 4:
                round3=dodaj(round3);break;
            case 5:
                round4=dodaj(round4);break;
            default:
                ostrz=new Alert("Uwaga","Maksymalna liczba rund wynosi 9", null, AlertType.INFO);
                ostrz.setTimeout(3000);
                ekran.setCurrent(ostrz);
        if(rundy.size()==1)
            rundy.append(repeat);
            rundy.addCommand(start);
        rundy.addCommand(delRound);
    else if(c==delRound)
        if(rundy.size()!=0)
            rundy.delete(rundy.size()-2);
            if (rundy.size()==1)
                rundy.deleteAll();
            if(rundy.size()==0)
                rundy.removeCommand(delRound);
                rundy.removeCommand(start);
    else if(c==start)
        ilrund=rundy.size()-1;
        if(this.repeat.size()>0)
            ilpowt=Integer.parseInt(this.repeat.getString());
        ekran = Display.getDisplay(this);
        for (i=1; i<=ilpowt;i++)
            odliczanie= new Form("Odliczanie");
             for (j=0;j<ilrund;j++)
                switch(j)
                     case 0:
                         odliczanie(round0);
                         break;
                     case 1:
                         odliczanie(round1);
                         break;
                     case 2:
                         odliczanie(round2);
                         break;
                     case 3:
                         odliczanie(round3);
                         break;
                     case 4:
                         odliczanie(round4);
                         break;
                     case 5:
                         odliczanie(round5);
                         break;
                     case 6:
                         odliczanie(round6);
                         break;
                     case 7:
                         odliczanie(round7);
                         break;
                     case 8:
                         odliczanie(round8);
                         break;
class Licznik extends Thread
    int czas1,k;
    Form forma;
    monitor m;
    public Licznik(int k,Form formap)
        czas1=k;
        forma=formap;
    public synchronized void run()
        while(czas1>0)
            forma.deleteAll();
            forma.append("Czas pozostały (s): "+czas1);
            try{Thread.sleep(1000);} catch(InterruptedException e){e.printStackTrace();}
            czas1--;
        if(czas1<=0)
            m.put();
    }and monitor class
public class monitor
boolean busy=false;
synchronized void get()
    if(!busy)
        try
            wait();
        }catch(InterruptedException e){e.printStackTrace();}
    notify();
synchronized void put()
    if(busy)
        try
        wait();
        }catch(InterruptedException e){e.printStackTrace();}
    busy=true;
    notify();
}Can anybody help me with this?

Groovemaker,
Your Licznik class has a member m of type monitor, which has not been instantiated (in other words is null) hence, when calling m.put() you get NullPointerException. Please also mind, that using Thread.sleep(1000) is not an accurate way of measuring time.
If I may, please use recommended for Java class naming conventions - some of your names use lower case, while other don't which is confusing to the reader.
Daniel

Problem with threads running javaw

Hi,
Having a problem with multi thread programming using client server sockets. The program works find when starting the the application in a console using java muti.java , but when using javaw multi.java the program doesnt die and have to kill it in the task manager. The program doesnt display any of my gui error messages either when the server disconnect the client. all works find in a console. any advice on this as I havent been able to understand why this is happening? any comment would be appreciated.
troy.

troy,
Try and post a minimum code sample of your app which
does not work.
When using javaw, make sure you redirect the standard
error and standard output streams to file.
Graeme.Hi Graeme,
I dont understand what you mean by redirection to file? some of my code below.
The code works fine under a console, code is supposed to exit when the client (the other server )disconnects. the problem is that but the clientworker side of the code still works. which under console it doesnt.
public class Server{
ServerSocket aServerSocket;
Socket dianosticsSocket;
Socket nPortExpress;
ClientListener aClientListener;
LinkedList queue = new LinkedList();
int port = 0;
int clientPort = 0;
String clientName = null;
boolean serverAlive = true;
* Server constructor generates a server
* Socket and then starts a client threads.
* @param aPort      socket port of local machine.
public Server(int aPort, String aClientName, int aClientPort){
port = aPort;
clientName = aClientName;
clientPort = aClientPort;
try{
// create a new thread
aServerSocket = new ServerSocket(port) ;
// connect to the nPortExpress
aClientListener = new ClientListener(InetAddress.getByName(clientName), clientPort, queue,this);
// aClientListener.setDaemon(true);
aClientListener.start();
// start a dianostic port
DiagnosticsServer aDiagnosticsServer = new DiagnosticsServer(port,queue,aClientListener);
// System.out.println("Server is running on port " + port + "...");
// System.out.println("Connect to nPort");
catch(Exception e)
// System.out.println("ERROR: Server port " + port + " not available");
JOptionPane.showMessageDialog(null, (e.toString()),"ERROR: Server port " + port + " not available", JOptionPane.ERROR_MESSAGE);
serverAlive = false;
System.exit(1);
while(serverAlive&&aClientListener.hostSocket.isConnected()){
try{
// connect the client
Socket aClient = aServerSocket.accept();
//System.out.println("open client connection");
//System.out.println("client local: "+ aClient.getLocalAddress().toString());
// System.out.println("client localport: "+ aClient.getLocalPort());
// System.out.println("client : "+ aClient.getInetAddress().toString());
// System.out.println("client port: "+ aClient.getLocalPort());
// make a new client thread
ClientWorker clientThread = new ClientWorker(aClient, queue, aClientListener, false);
// start thread
clientThread.start();
catch(Exception e)
//System.out.println("ERROR: Client connection failure");
JOptionPane.showMessageDialog(null, (e.toString()),"ERROR: Client connection failure", JOptionPane.ERROR_MESSAGE);
}// end while
} // end constructor Server
void serverExit(){
     JOptionPane.showMessageDialog(null, "Server ","ERROR: nPort Failure", JOptionPane.ERROR_MESSAGE);
     System.exit(1);
}// end class Server
*** connect to another server
public class ClientListener extends Thread{
InetAddress hostName;
int hostPort;
Socket hostSocket;
BufferedReader in;
PrintWriter out;
boolean loggedIn;
LinkedList queue;      // reference to Server queue
Server serverRef; // reference to main server
* ClientListener connects to the host server.
* @param aHostName is the name of the host eg server name or IP address.
* @param aHostPort is a port number of the host.
* @param aLoginName is the users login name.
public ClientListener(InetAddress aHostName, int aHostPort,LinkedList aQueue,Server aServer)      // reference to Server queue)
hostName = aHostName;
hostPort = aHostPort;
queue = aQueue;
serverRef = aServer;
// connect to the server
try{
hostSocket = new Socket(hostName, hostPort);
catch(IOException e){
//System.out.println("ERROR: Connection Host Failed");
JOptionPane.showMessageDialog(null, (e.toString()),"ERROR: Connection to nPort Failed", JOptionPane.ERROR_MESSAGE);
System.exit(0);
} // end constructor ClientListener
** multi client connection server
ClientWorker(Socket aSocket,LinkedList aQueue, ClientListener aClientListener, boolean diagnostics){
queue = aQueue;
addToQueue(this);
client = aSocket;
clientRef = aClientListener;
aDiagnostic = diagnostics;
} // end constructor ClientWorker
* run method is the main loop of the server program
* in change of handle new client connection as well
* as handle all messages and errors.
public void run(){
boolean alive = true;
String aSubString = "";
in = null;
out = null;
loginName = "";
loggedIn = false;
while (alive && client.isConnected()&& clientRef.hostSocket.isConnected()){
try{
in = new BufferedReader(new InputStreamReader(client.getInputStream()));
out = new PrintWriter(new OutputStreamWriter(client.getOutputStream()));
if(aDiagnostic){
out.println("WELCOME to diagnostics");
broadCastDia("Connect : diagnostics "+client.getInetAddress().toString());
out.flush();
else {
out.println("WELCOME to Troy's Server");
broadCastDia("Connect : client "+client.getInetAddress().toString());
     out.flush();
String line;
while(((line = in.readLine())!= null)){
StringTokenizer aStringToken = new StringTokenizer(line, " ");
if(!aDiagnostic){
broadCastDia(line);
clientRef.sendMessage(line); // send mesage out to netExpress
out.println(line);
out.flush();
else{
if(line.equals("GETIPS"))
getIPs();
else{
clientRef.sendMessage(line); // send mesage out to netExpress
out.println(line);
out.flush();
} // end while
catch(Exception e){
// System.out.println("ERROR:Client Connection reset");
                         JOptionPane.showMessageDialog(null, (e.toString()),"ERROR:Client Connection reset", JOptionPane.ERROR_MESSAGE);
try{
if(aDiagnostic){
broadCastDia("Disconnect : diagnostics "+client.getInetAddress().toString());
out.flush();
else {
broadCastDia("Disconnect : client "+client.getInetAddress().toString());
     out.flush();
// close the buffers and connection;
in.close();
out.close();
client.close();
// System.out.println("out");
// remove from list
removeThreadQueue(this);
alive = false;
catch(Exception e){
// System.out.println("ERROR: Client Connection reset failure");
JOptionPane.showMessageDialog(null, (e.toString()),"ERROR: Client Connection reset failure", JOptionPane.ERROR_MESSAGE);
}// end while
} // end method run
* method run - Generates io stream for communicating with the server and
* starts the client gui. Run also parses the input commands from the server.
public void run(){
boolean alive = true;
try{
// begin to life the gui
// aGuiClient = new ClientGui(hostName.getHostName(), hostPort, loginName, this);
// aGuiClient.show();
in = new BufferedReader(new InputStreamReader(hostSocket.getInputStream()));
out = new PrintWriter(new OutputStreamWriter(hostSocket.getOutputStream()));
while (alive && hostSocket.isConnected()){
String line;
while(((line = in.readLine())!= null)){
System.out.println(line);
broadCast(line);
} // end while
} // end while
catch(Exception e){
//     System.out.println("ERRORa Connection to host reset");
JOptionPane.showMessageDialog(null, (e.toString()),"ERROR: Connection to nPort reset", JOptionPane.ERROR_MESSAGE);
try{
hostSocket.close();
     }catch(Exception a){
     JOptionPane.showMessageDialog(null, (a.toString()),"ERROR: Exception", JOptionPane.ERROR_MESSAGE);
alive = false;
System.exit(1);
} // end method run

Problem with Threads and "plase wait..."-Window

Hi everyone,
I have a problem that I'm not able to solve in any way... I have a time-consuming task (a file decryption) which I execute in a separate thread; I've used the SwingWorker class, like suggested by sun-tutorial, and it works right. The problem is that I have to wait that the decryption have finished before continuing with program-execution. Therefore I would like to display a "please wait"-window while the task runs. I've tryed all the possible ways I know but the problem is always the same: the waitWindow is displayed empty, the bounds are painted but the contents no; it's only painted when the decrypt-task has finished. Please help me, I have no more resources....
decrypt-file code:
public class DecryptFile {
private String cryptedFileNameAndPath;
private ByteArrayInputStream resultStream = null;
// need for progress
private int lengthOfTask;
private int current = -1;
private String statMessage;
public DecryptFile(String encZipFileNameAndPath) {
    cryptedFileNameAndPath = encZipFileNameAndPath;
    //Compute length of task...
    // 0 for indeterminate
    lengthOfTask = 0;
public ByteArrayInputStream getDecryptedInputStream() {
    return this.resultStream;
   * Called from ProgressBarDemo to start the task.
public void go() {
    current = -1;
    final SwingWorker worker = new SwingWorker() {
      public Object construct() {
        return new ActualTask();
    worker.start();
   * Called from ProgressBarDemo to find out how much work needs
   * to be done.
public int getLengthOfTask() {
    return lengthOfTask;
   * Called from ProgressBarDemo to find out how much has been done.
public int getCurrent() {
    return current;
public void stop() {
    current = lengthOfTask;
   * Called from ProgressBarDemo to find out if the task has completed.
public boolean done() {
    if (current >= lengthOfTask)
      return true;
    else
      return false;
public String getMessage() {
    return statMessage;
   * The actual long running task. This runs in a SwingWorker thread.
class ActualTask {
    ActualTask () {
      current = -1;
      statMessage = "";
      resultStream = AIUtil.getInputStreamFromEncZip(cryptedFileNameAndPath); //here the decryption happens
      current = 0;
      statMessage = "";
}The code that calls decryption and displays waitWindow
      final WaitSplash wS = new WaitSplash("Please wait...");
      final DecryptFile cryptedTemplate = new DecryptFile (this.templateFile);
      cryptedTemplate.go();
      while (! cryptedTemplate.done()) {
        try {
          wait();
        } catch (Exception e) { }
      this.templateInputStream = cryptedTemplate.getDecryptedInputStream();
      wS.close();Thanks, thanks, thanks in advance!
Edoardo

Maybe you can try setting the priority of the long-running thread to be lower? so that the UI will be more responsive...

Problem with threads and simulation: please help

please help me figure this out..
i have something like this:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class DrawShapes extends JApplet{
     private JButton choices[];
     private String names[]={"line", "square", "oval"};
     private JPanel buttonPanel;
     private DrawPanel drawingArea;
     private int width=300, height=200;
     public void init(){
          drawingArea=new DrawPanel(width, height);
          choices=new JButton[names.length];
          buttonPanel=new JPanel();
          buttonPanel.setLayout(new GridLayout(1, choices.length));
          ButtonHandler handler=new ButtonHandler();
          for(int i=0; i<choices.length; i++){
               choices=new JButton(names[i]);
               buttonPanel.add(choices[i]);
               choices[i].addActionListener(handler);
          Container c=getContentPane();
          c.add(buttonPanel, BorderLayout.NORTH);
          c.add(drawingArea, BorderLayout.CENTER);
     }//end init
     public void setWidth(int w){
          width=(w>=0 ? w : 300);
     public void setHeight(int h){
          height=(h>=0 ? h : 200);
     /*public static void main(String args[]){
          int width, height;
          if(args.length!=2){
               height=200; width=300;
          else{
                    width=Integer.parseInt(args[0]);
                    height=Integer.parseInt(args[1]);
          JFrame appWindow=new JFrame("An applet running as an application");
          appWindow.addWindowListener(
               new WindowAdapter(){
                    public void windowClosing(WindowEvent e){
                         System.exit(0);
          DrawShapes appObj=new DrawShapes();
          appObj.setWidth(width);
          appObj.setHeight(height);
          appObj.init();
          appObj.start();
          appWindow.getContentPane().add(appObj);
          appWindow.setSize(width, height);
          appWindow.show();
     }//end main*/
     private class ButtonHandler implements ActionListener{
          public void actionPerformed(ActionEvent e){
               for(int i=0; i<choices.length; i++){
                    if(e.getSource()==choices[i]){
                         drawingArea.setCurrentChoice(i);
                         break;
}//end class DrawShapes
class DrawPanel extends JPanel{
     private int currentChoice=-1;
     private int width=100, height=100;
     public DrawPanel(int w, int h){
          width=(w>=0 ? w : 100);
          height=(h>=0 ? h : 100);
     public void paintComponent(Graphics g){
          super.paintComponent(g);
          switch(currentChoice){
               case 0:     g.drawLine(randomX(), randomY(), randomX(), randomY());
                         break;
               case 1: g.drawRect(randomX(), randomY(), randomX(), randomY());
                         break;
               case 2: g.drawOval(randomX(), randomY(), randomX(), randomY());
                         break;
     public void setCurrentChoice(int c){
          currentChoice=c;
          repaint();
     private int randomX(){
          return (int) (Math.random()*width);
     private int randomY(){
          return (int) (Math.random()*height);
}//end class drawPanel
That one's from a book. I used that code to start with my applet. Mine calls different merthod from the switch cases. Say I have:
case 0: drawStart(g); break;
public void drawStart(Graphics g){
/* something here */
drawMain(g);
public void drawMain(graphics g){
g.drawString("test", x, y);
//here's where i'm trying to pause
//i've tried placing Thread.sleep between these lines
g.drawLine(x, y, a, b);
//Thread.sleep here
g.drawRect(x, y, 50, 70);
}I also need to put delays between method calls but I need to synchronize them. Am I doing it all wrong? The application pauses or sleeps but afterwards, it still drew everything all at once. Thanks a lot!

It is. Sorry about that. Just answer any if you want to. I'd appreciate your help. Sorry again if it caused you anything or whatever. .n_n.

Problem with threads in j2me

im using jdk 1.6 with java wtk 2.1
ya i know..
2.1 is a jdk1.4 source
but im using souce as 1.4 during compiliation so thats not the prob
this is my code
package org.learn;
import javax.microedition.midlet.MIDlet;
import javax.microedition.lcdui.Alert;
import javax.microedition.lcdui.Display;
public class thtest extends MIDlet
Thread t;
public void startApp()
Alert a=new Alert("hello");
a.setString("hello");
Alert b=new Alert("world");
b.setString("world");
Display d = Display.getDisplay(this );
d.setCurrent(a);
t=Thread.currentThread();
try{
t.sleep(10000);
catch (Exception e){}
d.setCurrent(b);
public void pauseApp()
public void destroyApp(boolean unconditional)
its just supposed to pause between the alerts using threads
however when i run it using the wtk, the emulator run properly but when i launch the app, it stops executing giving me this:
"Error verifying method org/learn/thtest startApp()V
Approximate bytecode offset 49: Inconsistent or missing stackmap at target
%the stack info%
Execution completed.
437782 bytecodes executed
9 thread switches
486 classes in the system (including system classes)
2506 dynamic objects allocated (73832 bytes)
2 garbage collections (60652 bytes collected)
Execution completed.
437782 bytecodes executed
9 thread switches
486 classes in the system (including system classes)
ALERT: java/lang/VerifyError: org/learn/thtest.
2506 dynamic objects allocated (73832 bytes)
2 garbage collections (60652 bytes collected)
please can someone help me out with this, is it an error on my part or do i have to set some option.

Hi gandalf123,
First, Thread.sleep is a static method, so you don't need to create a Thread object to use it.
I think the problem is due to the fact you don't preverify your midlet.
More over, you don't need to double post your question.

Problem with threads communication

Hi All
I have a multithreaded application in which I have 3 threads running including main thread. One of the thread (Thread1) spawned by main thread is performing the business logic required. The other one (Thread 2) is just to send the periodic signals to an admin application that it is alive. Now I need to pass some data obtained from business logic (Thread1) to the second thread (Thread2). How can i do that.? I need the data from Thread1 to Thread2 every time, the thread2 send the alive request to admin application.
Thanks & Regards
Inder Jeet Singh

See Producer/Consumer example at for 2 threads exchanging data:
http://java.sun.com/docs/books/tutorial/essential/threads/synchronization.html
In your case it seems reasonable to store data somewhere until T2 will use it during sending
alive request to admin application

Problem with threads and graphics

I have a thread that chooses paths for a Travelling salesman problem, it then calls a TSPdraw class and passes it the path, which the class then draws. the problem is when i have two threads it creates two windows but only draws a path in one of them. any ideas where i`m going wrong

Are you using swing components? Swing isn't threadsafe. If you have multiple threads that want to update your UI you need to use the SwingUtilities.invokeLater(...)or invokeAndWait(...). There is a page in the swing tutorial about this at: http://java.sun.com/docs/books/tutorial/uiswing/misc/threads.html

Problem with threads hanging

We have a problem where our application stops responding after a few days of usage. Things will for fine for a day or two, and then pretty quickly threads will start getting hung up, usually in places where they are allocating memory
We are running WebLogic 8.1 SP2 on Sun JDK 1.4.2_04 on Solaris 8 using the alternate threading model and the -server hotspot vm. We are running pretty much the same code that we had no problems with under WebLogic 6.1 SP4 and Sun JDK 1.3.1.
A thread dump usually shows that some or all of our execute threads are in the state "waiting for monitor entry" even though they are not currently waiting on any java locks. Here is a sample thread from the thread dump (we have ~120 threads so I don't want to post the full dump).
=============================================================================================
"ExecuteThread: '8' for queue: 'itgCrmWarExecutionQueue'" daemon prio=5 tid=0x005941d0 nid=0x2c waiting for monitor entry [c807f000..c807fc28]
at java.lang.String.substring(String.java:1446)
at java.lang.String.substring(String.java:1411)
at weblogic.servlet.internal.ServletRequestImpl.getRelativeUri(ServletRequestImpl.java:1872)
at weblogic.servlet.internal.WebAppServletContext.invokeServlet(WebAppServletContext.java:3492)
at weblogic.servlet.internal.ServletRequestImpl.execute(ServletRequestImpl.java:2585)
at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:197)
at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:170)
=============================================================================================
String.java line 1446 for this jdk allocates a new String object, and all the other threads in this state also are creating new objects or arrays, etc.
We've done a pstack on this process when it's in this state, and the threads that are in the "waiting for monitor entry" that look like they're allocating memory are all waiting on the same lwp_mutex_lock with some allocation method that's calling into the native TwoGenerationCollectorPolicy.mem_allocate_work (see pstack output below for the same thread as in the thread dump above)
=============================================================================================
----------------- lwp# 44 / thread# 44 --------------------
ff31f364 lwp_mutex_lock (e3d70)
fee92384 __1cNObjectMonitorGenter26MpnGThread__v_ (5000, 525c, 5000, 50dc, 4800, 4af0) + 2d8
fee324d4 __1cSObjectSynchronizerKfast_enter6FnGHandle_pnJBasicLock_pnGThread__v_ (c807f65c, c807f7d4, 5941d0, 0, 35d654, fee328ec) + 68
fee32954 __1cQinstanceRefKlassZacquire_pending_list_lock6FpnJBasicLock__v_ (c807f7d4, ff170000, d4680000, 4491d4, fee1bc2c,
0) + 78
fee3167c __1cPVM_GC_OperationNdoit_prologue6M_i_ (c807f7bc, 4400, ff170000, 2d2b8, 4a6268, c807fa18) + 38
fee2e0b0 __1cIVMThreadHexecute6FpnMVM_Operation__v_ (c807f7bc, 963a8, 0, 0, 1, 0) + 90
fed2c2a4 __1cbCTwoGenerationCollectorPolicyRmem_allocate_work6MIii_pnIHeapWord__ (962c0, ff1c29ec, ff1c297c, ff131a26, 4800, 4998) + 160
fed22940 __1cNinstanceKlassRallocate_instance6MpnGThread__pnPinstanceOopDesc__ (ee009020, 5941d0, 15ca581, 3647f0, 4a6268, c807f8c8) + 180
fed34928 __1cLOptoRuntimeFnew_C6FpnMklassOopDesc_pnKJavaThread__v_ (ee009018, 5941d0, 0, 0, 0, 0) + 28
fa435a58 ???????? (ee009018, e86de, 15ca4de, 50dc, 5941d0, c807f9c8)
fb36f9a4 ???????? (0, d412ccd8, ee046c28, ff170000, 0, 0)
fad8b278 ???????? (ee046c28, d6000c90, ee046530, 8, db8e8450, c807f9e8)
fad62abc ???????? (d412ccd8, ee046530, d6000c90, ee3bfa38, 8, c807fa18)
fa4b3c38 ???????? (c807fb9c, 0, f2134700, fa415e50, 8, c807faa8)
fa40010c ???????? (c807fc28, c807fe90, a, ee9e1e20, 4, c807fb40)
fed5d48c __1cJJavaCallsLcall_helper6FpnJJavaValue_pnMmethodHandle_pnRJavaCallArguments_pnGThread__v_ (c807fe88, c807fcf0, c807fda8, 5941d0, 5941d0, c807fd00) + 27c
fee4b784 __1cJJavaCallsMcall_virtual6FpnJJavaValue_nLKlassHandle_nMsymbolHandle_4pnRJavaCallArguments_pnGThread__v_ (ff170000, 594778, c807fd9c, c807fd98, c807fda8, 5941d0) + 164
fee5e8dc __1cJJavaCallsMcall_virtual6FpnJJavaValue_nGHandle_nLKlassHandle_nMsymbolHandle_5pnGThread__v_ (c807fe88, c807fe84, c807fe7c, c807fe74, c807fe6c, 5941d0) + 6c
fee6fc74 __1cMthread_entry6FpnKJavaThread_pnGThread__v_ (5941d0, 5941d0, 838588, 594778, 306d10, fee69254) + 128
fee6927c __1cKJavaThreadDrun6M_v_ (5941d0, 2c, 40, 0, 40, 0) + 284
fee6575c _start   (5941d0, fa1a1600, 0, 0, 0, 0) + 134
ff3758c0 lwpstart (0, 0, 0, 0, 0, 0)
=============================================================================================
Also when it's having this problem, the "VM Thread" is always using a lot of processor time. We did a couple of pstacks today while it was having this problem, and this thread was stuck in the ONMethodSweeper.sweep for over 15 minutes when we finally killed the server.
From the thread dump:
"VM Thread" prio=5 tid=0x000e2d20 nid=0x2 runnable
From the first pstack:
=============================================================================================
----------------- lwp# 2 / thread# 2 --------------------
fed40c04 __1cXvirtual_call_RelocationIparse_ic6FrpnICodeBlob_rpC5rppnHoopDesc_pi_nNRelocIterator__ (42a2f4, fa5fa46d, ffffffff, fc4ffcb8, 42a2f4, 42a324) + 124
fed46318 __1cKCompiledIC2t5B6MpnKRelocation__v_ (42a2f0, fc4ffd24, fc4ffd4c, e802, 0, 6) + 38
fed90c38 __1cHnmethodVcleanup_inline_caches6M_v_ (fa5f7f88, fa608940, 1, 0, fa400000, 6) + 1ac
fede18b4 __1cONMethodSweeperFsweep6F_v_ (2cf38, 0, ffffffff, ff1cf1fc, ff1c66e8, fede1d44) + 1b0
fede1e6c __1cUSafepointSynchronizeFbegin6F_v_ (2cf38, ff1ba138, 5000, 50dc, 5000, 525c) + 248
feef1fd4 __1cIVMThreadEloop6M_v_ (4400, 4000, 4324, 4000, 42b0, 3800) + 3d4
feef1ae4 __1cIVMThreadDrun6M_v_ (e2d20, 2, 40, 0, 40, 0) + 8c
fee6575c _start   (e2d20, ff270200, 0, 0, 0, 0) + 134
ff3758c0 lwpstart (0, 0, 0, 0, 0, 0)
=============================================================================================
Second pstack
=============================================================================================
----------------- lwp# 2 / thread# 2 --------------------
fed41180 __1cXvirtual_call_RelocationIparse_ic6FrpnICodeBlob_rpC5rppnHoopDesc_pi_nNRelocIterator__ (0, ff1b9664, ffffffff, fc4ffcb8, a6f2cc, fc4ffbd0) + 6a0
fed46318 __1cKCompiledIC2t5B6MpnKRelocation__v_ (a6f2c8, fc4ffd24, fc4ffd4c, e802, 0, 6) + 38
fed90c38 __1cHnmethodVcleanup_inline_caches6M_v_ (faded4c8, fadf2c80, 1, 0, fa400000, 6) + 1ac
fede18b4 __1cONMethodSweeperFsweep6F_v_ (2cf38, 0, ffffffff, ff1cf1fc, ff1c66e8, fede1d44) + 1b0
fede1e6c __1cUSafepointSynchronizeFbegin6F_v_ (2cf38, ff1ba138, 5000, 50dc, 5000, 525c) + 248
feef1fd4 __1cIVMThreadEloop6M_v_ (4400, 4000, 4324, 4000, 42b0, 3800) + 3d4
feef1ae4 __1cIVMThreadDrun6M_v_ (e2d20, 2, 40, 0, 40, 0) + 8c
fee6575c _start   (e2d20, ff270200, 0, 0, 0, 0) + 134
ff3758c0 lwpstart (0, 0, 0, 0, 0, 0)
=============================================================================================
Has anyone ever seen anything like this? I'm trying to figure out if this is caused by something we're doing, or something relating to our environment and jvm options. Any ideas?

Thanks for the reply - I'm testing our app with the +UseConcMarkSweepGC now in our test environment to make sure it doesn't cause any problems there. Unfortunately the only place we've had this problem is on the production server, so it's extra difficult debugging this.
We're using the following memory options:
-ms512m -mx512m -XX:NewSize=128m -XX:PermSize=192m -XX:MaxNewSize=128m -XX:MaxPermSize=192m -XX:SurvivorRatio=8and the following debugging options, as we've also been seeing OutOfMemoryErrors ( see http://forum.java.sun.com/thread.jsp?forum=37&thread=522354&tstart=45&trange=15 )
-verbosegc -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+PrintHeapAtGCBTW, which c++filt version and options are you using? Our Solaris boxes only seem to have the GNU version installed. I was trying to run that on some of the other stack traces and wasn't getting anywhere, and didn't know if because it was GNU version wouldn't work on something compiled with the Sun compiler.
Thanks!
--Andy

Problem with threads and ProgressMonitor

Dear Friends:
I have a little problem with a thread and a ProgressMonitor. I have a long time process that runs in a thread (the thread is in an separate class). The thread has a ProgressMonitor that works fine and shows the tasks progress.
But I need deactivate the main class(the main class is the user interface) until the thread ends.
I use something like this:
LongTask myTask=new LongTask();
myTask.start();
myTask.join();
Now, the main class waits for the task to end, but the progress monitor don`t works fine: it shows only the dialog but not the progress bar.
What's wrong?

Is the dialog a modal dialog? This can block other UI updates.
In general, you should make sure that it isn't modal, and that your workThread has a fairly low priority so that the UI can do its updating

Problem with threads...

HI friends...
I am trying to make a server with a logging facility...
Let me explain the schema of the process...
1. the server starts as a thread and listens on port 9999 for any client.
2. when a client is accepted a PROCESS thread is started and the server gets back to listening.
3. now the PROCESS thread starts a initializes a LOGGER and listens the inputstream for any message from the client. the LOGGER initializes a log file and when a message is recieved it writes to the log file.
4. when a second client is connected to the server steps 2 and 3 take place.
but now the problem is ... when the second client connects to the server, the logger stops writing the messages of the first client to log1 but continues writing the messages of client1 & client2 to log2.
please give me a solution for this.
i can send you the project if you want to take a look at it.
thanx in advance...

hi friends i thought i would send the code to your personal email when wanted so i didnot paste it here...
anyway i made a test project where i am having the same problem..
Test.java
package testproject;
public class Test {
public Test() {
    for(int i = 0; i< 5; i++){
      TestThread thread = new TestThread();
      thread.start();
public static void main(String[] args){
    new Test();
TestThread.java
package testproject;
public class TestThread extends Thread{
public TestThread() {
public void run(){
    System.out.println(this.getName());
    Logger logger = new Logger(this.getName());
    while(true){
      logger.writeLog(this.getName());
      try {
        sleep(100);
      catch (InterruptedException ex) {
Logger.java:
package testproject;
import java.io.*;
public class Logger {
File logfile;
public static BufferedWriter FilewriteLOG;
public Logger(String dir) {
    makeDir(dir);
    System.out.println("log: " + logfile);
    try {
      FilewriteLOG = new BufferedWriter(new FileWriter(logfile));
    catch (IOException ex) {
public static void writeLog(String str) {
    try {
      FilewriteLOG.write(str + "\n");
      FilewriteLOG.flush();
    catch (IOException ex) {
      ex.printStackTrace();
private void makeDir(String clientID) {
    String dir = "logs/" + clientID;
    String file = System.currentTimeMillis() + "";
    boolean exist = (new File(dir)).exists();
    if (exist) {
      makeFile(dir, file);
    else {
      new File(dir).mkdir();
      makeFile(dir, file);
private void makeFile(String dir, String fileName) {
    logfile = new File(dir + "/" + fileName + ".txt");
    try {
      logfile.createNewFile();
      FilewriteLOG = new BufferedWriter(new FileWriter(logfile));
    catch (IOException ex) {

New DVR Issues (First Run, Channel Switching, etc.)

I've spent the last 30 minutes trying to find answers through the search with no luck, so sorry if I missed something.
I recently switched to FIOS from RCN cable in New York. I've gone through trying to setup my DVR and am running into issues and was hoping for some answers.
1. I setup two programs to record at 8PM, I was watching another channel at the time and only half paying attention. Around 8:02 I noticed a message had popped up asking if I would like to switch channels to start recording. I was expecting it to force it to switch like my old DVR, but in this case it didn't switch and I missed the first two minutes of one of the shows. I typically leave my DVR on all day and just turn off the TV, this dual show handling will cause issues with that if I forget to turn off the DVR. Is there a setting I can change that will force the DVR to choose one of the recording channels?
2. I setup all my recordings for "First Run" because I only want to see the new episodes. One show I setup was The Daily Show on comedy central, which is shown weeknights at 11pm and repeated 3-4 times throughout the day. My scheduled recordings is showing all these as planned recordings even though only the 11pm show is really "new". Most of the shows I've setup are once a week so they aren't a problem, but this seems like it will quickly fill my DVR. Any fixes?
Thanks for the help.
Solved!
Go to Solution.

I came from RCN about a year ago. Fios is different in several ways, not all of them desirable. Here are several ways to get--and fix--unwanted recordings from a series recording setup.
Some general principles.
Saving changes. When you originally create a series with options, or if you go back to edit the options for an existing series, You MUST save the Series Options changes. Pretty much everywhere else in the user interface, when you change an option, the change takes effect immediately--but not in Series Options. Look at the Series Options window. Look at the far right side. There is a vertical "Save" bar, which you must navigate to and click OK on to actually save your changes. Exiting the Series Options window without having first saved your changes loses all your attempted changes--immediately.
Default Series Options. This is accessed from [Menu]--DVR--Settings--Default Series Options. This will bring up the series options that will automatically be applied to the creation of a NEW series. The options for every previously created series will not be affected by a subsequent modification of the Default Series Options. You should set these options to the way you would like them to be for the majority of series recordings that you are likely to create. Be sure to SAVE your changes. This is what you will get when you select "Create Series Recording" from the Guide. When creating a new series recording where you think that you may want options different from the default, select "Create Series with Options" instead. Series Options can always be changed for any individual series set up later--but not for all series at once.
Non-series recordings. With Fios you have no directly available options for these. With RCN and most other DVRs, you can change the start and end times for individual episodes, including individual episodes that are also in a series. With Fios, your workarounds are to create a series with options for a single program, then delete the series later; change the series options if the program is already in a series, then undo the changes you made to the series options later; or schedule recordings of the preceding and/or following shows as needed.
And now, to the unwanted repeats.
First, make sure your series options for the specific series in question--and not just the series default options--include "First Run Only". If not, fix that and SAVE. Then check you results by viewing the current options using the Series Manager app under the DVR menu.
Second, and most annoying, the Guide can have repeat programs on your channel tagged as "New". It happens. Set the series option "Air Time" to "Selected Time". To make this work correctly, you must have set up the original series recording after selecting the program in the Guide at the exact time of a first run showing (11pm, in your case), and not on a repeat entry in the Guide. Then, even it The Daily Show is tagged as New for repeat showings, these will be ignored.
Third, another channel may air reruns of the program in your series recording, and the first showing of a rerun episode on the other channel may be tagged as "New". These can be ignored in your series if you set the series option "Channel" to "Selected Channel". Related to this, if there is both an SD and HD channel broadcasting you series program, you will record them both if the series option "Duplicates" is set to "Yes". However, when the Channel option is set to "Selected Channel", the Duplicates Option is always effectively "No", regardless of what shows up on the options screen.
As for you missing two minutes, I have sereral instances in which two programs start recording at the same time. To the best of my recollection, whenever the warning message has appeared, ignoring it has not caused a loss of recording time. You might have an older software version. Newest is v.1.8. Look at Menu--Settings--System Info. Or, I might not have noticed the loss of minutes. I regularly see up to a minute of previous programming at the start of a recording, or a few missing seconds at the beginning or end of a recording. There are a lot of possibilities for that, but the DVR clock being incorrect is not one of them. With RCN, the DVR clocks occasionally drifted off by as much as a minute and a half.

10.6.8 to 10.8.2 on mac mini no longer needed as a server

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