Optimizing the # of threads to do code optimization

Hi:
Is the number of threads used in the server to perform the code optimization tuneable? Cust has a large app and server startup is VERY long (1hour+)
vs 15 mins with -Xnoopt) due to optimization processing. Can the # threads used for this be increased via some start switch?
thx.
/W

Try with -XXoptthreads, reference here:
http://download.oracle.com/docs/cd/E13150_01/jrockit_jvm/jrockit/jrdocs/refman/optionXX.html#wp1024195
I believe the default is 1, try using 2 instead. More than that probably won't help much unless it's a large server (many CPUs).
Henrik

Similar Messages

Need help in optimizing the ABAP code

Hi,
Can anyone help me in optimizing the code. Here the select statement has select within the loop. Need help in optimization.
WHEN '0CO_PC_PCP_03'.
LOOP AT C_T_DATA INTO TBL_KKBW_ITEM.
      W_TABIX = SY-TABIX.
      IF TBL_KKBW_ITEM-CURRENCY_TYPE EQ '20'.
SELECT SINGLE KALNR KALKA KADKY TVERS KADAT KOKRS INTO (W_KALNR, W_KALKA, W_KADKY, W_TVERS,
                TBL_KKBW_ITEM-COSTING_DATE,
                TBL_KKBW_ITEM-CONTROLLING_AREA)
                FROM KEKO
                   WHERE KLVAR EQ TBL_KKBW_ITEM-COSTING_VARIANT
                    AND KADKY EQ TBL_KKBW_ITEM-COSTING_DATE
                    AND TVERS EQ TBL_KKBW_ITEM-COSTING_VERSION
                    AND MATNR EQ TBL_KKBW_ITEM-HEADER_MATERIAL
                    AND WERKS EQ TBL_KKBW_ITEM-HEADER_PLANT.
           IF SY-SUBRC EQ 0.
          SELECT SINGLE KOSTL INTO TBL_KKBW_ITEM-COST_CENTER
                          FROM CKIS WHERE KOSTL NE SPACE
                                     AND KALNR EQ W_KALNR
                                     AND KALKA EQ W_KALKA
                                     AND KADKY EQ W_KADKY
                                     AND TVERS EQ W_TVERS.
          IF SY-SUBRC NE 0.
            CLEAR TBL_KKBW_ITEM-COST_CENTER.
          ENDIF.
        ENDIF.
        MODIFY C_T_DATA FROM TBL_KKBW_ITEM INDEX W_TABIX.
      ELSE.
        DELETE C_T_DATA INDEX W_TABIX.
      ENDIF.
    ENDLOOP.
Thanks,
Rani.

hi
plz use the below code :
WHEN '0CO_PC_PCP_03'.
SELECT KALNR KALKA KADKY TVERS KADAT KOKRS INTO it_keko "declare internal table with the mentioned fields
" also select the fields to be used in where condition
FROM KEKO
for all entries in c_t_data
WHERE KLVAR EQ c_t_data-COSTING_VARIANT
AND KADKY EQ c_t_data-COSTING_DATE
AND TVERS EQ c_t_data-COSTING_VERSION
AND MATNR EQ c_t_data-HEADER_MATERIAL
AND WERKS EQ c_t_data-HEADER_PLANT.
"sort the tables on the fields used in where.
IF SY-SUBRC EQ 0.
SELECT KOSTL "and other fields to be used in where
INTO it _ckis
FROM CKIS
for all entries in c_t_data
WHERE KOSTL NE SPACE "use c_t_data
AND KALNR EQ W_KALNR
AND KALKA EQ W_KALKA
AND KADKY EQ W_KADKY
AND TVERS EQ W_TVERS.
IF SY-SUBRC NE 0.
CLEAR TBL_KKBW_ITEM-COST_CENTER.
ENDIF.
it_data[] = c_t_data. "declare it_data same as the extract structure
delete it_data where CURRENCY_TYPE NE '20'.
LOOP AT it_data assigning <fs_data>. "use field symbols
read from it_keko into wa_keko
where
KLVAR EQ <fs_data>-COSTING_VARIANT
AND KADKY EQ <fs_data>-COSTING_DATE
AND TVERS EQ <fs_data>-COSTING_VERSION
AND MATNR EQ <fs_data>-HEADER_MATERIAL
AND WERKS EQ<fs_data>-HEADER_PLANT
binary search.
if sy_subrc = 0.
similarly read from the second itab
ENDIF.
ENDLOOP.
c_t_data[] = it_data[].
Pls let me know in case of any issues
Regards,
Aparna
Edited by: Aparna KS on Jun 13, 2010 11:01 PM

Internal table(Optimizing the codes)

Dear all,
Please help me in optimizing the following codes..
FORM fetch_item_data1 .
CLEAR itab_zsbhdr .
LOOP AT itab_zsbhdr .
    IF itab_zsbhdr-bedae = 'SPI'.
      SELECT * FROM zioel2 INTO i_zioel
                    WHERE ordr = itab_zsbhdr-vbeln
                    AND item = itab_zsbhdr-posnr
                    AND vdatu = itab_zsbhdr-vdatu .
        APPEND i_zioel.
        CLEAR i_zioel .
      ENDSELECT .
    ENDIF .
ENDLOOP .
ENDFORM.                    " FETCH_ITEM_DATA1
MY DOUBT:
For example if you all can see the select statement,,there we can also write as,
data : itab_zsbhdr_dummy like itab_zsbhdr occurs 0 with header line.
CLEAR itab_zsbhdr .
itab_zsbhdr_dummy[] = itab_zsbhdr[].
DELETE itab_zsbhdr_DUMMY[] WHERE bedat NE 'SPI'.
SELECT * FROM zioel2 appending table i_zioel
             for all entries in itab_zsbhdr_DUMMY
                 WHERE ordr = itab_zsbhdr_dummy-vbeln
                 AND item = itab_zsbhdr_dummy-posnr
                 AND vdatu = itab_zsbhdr_dummy-vdatu .
So now we can see there is no append and modify.
So my question is ,,"Is it the right way to go?"
Again i am taking off the loop & instead deleting those date not equals to SPI.
So please help me by either confirming me with this particular optimization or give me some other optimized codes on this regard.
Thanx.

hye..
i am inserting my comments
FORM fetch_item_data1 .
CLEAR itab_zsbhdr .
You have cleared the internal table, so the content is empty.. hence it will not enter into the loop.
LOOP AT itab_zsbhdr .
IF itab_zsbhdr-bedae = 'SPI'.
SELECT * FROM zioel2 INTO i_zioel
WHERE ordr = itab_zsbhdr-vbeln
AND item = itab_zsbhdr-posnr
AND vdatu = itab_zsbhdr-vdatu .
Never use a select in a loop, this means ur hitting the database n number of times which is not at all recommondable.
APPEND i_zioel.
CLEAR i_zioel .
ENDSELECT .
instead of using select and end select it can be directly writen into
select * from [dbtab] into table [itab] for all entreis in it_comparision
where [field] = it_comparision-field.
ENDIF .
ENDLOOP .
ENDFORM. " FETCH_ITEM_DATA1
Yeah ur second code is more recommmended with these modifications.
hope this is useful.
thnks.
imran.

Why can't I interrupt the main thread from a child thread with this code?

I am trying to find an elegant way for a child thread (spawned from a main thread) to stop what its doing and tell the main thread something went wrong. I thought that if I invoke mainThread.interrupt() from the child thread by giving the child thread a reference to the main thread, that would do the trick. But it doesn't work all the time. I want to know why. Here's my code below:
The main class:
* IF YOU RUN THIS OFTEN ENOUGH, YOU'LL NOTICE THE "Child Please!" MESSAGE NOT SHOW AT SOME POINT. WHY?
public class InterruptingParentFromChildThread
     public static void main( String args[] )
          Thread child = new Thread( new ChildThread( Thread.currentThread() ) );
          child.start();
          try
               child.join();
          catch( InterruptedException e )
// THE LINE BELOW DOESN'T GET PRINTED EVERY SINGLE TIME ALTHOUGH IT WORKS MOST TIMES, WHY?
               System.out.println( "Child please!" );
          System.out.println( "ALL DONE!" );
The class for the child thread:
public class ChildThread implements Runnable
     Thread mParent;
     public ChildThread( Thread inParent )
          mParent = inParent;
     public void run()
          System.out.println( "In child thread." );
          System.out.println( "Let's interrupt the parent thread now." );
          // THE COMMENTED OUT LINE BELOW, IF UNCOMMENTED, DOESN'T INVOKE InterruptedException THAT CAN BE CAUGHT IN THE MAIN CLASS' CATCH BLOCK, WHY?
          //Thread.currentThread().interrupt();
          // THIS LINE BELOW ONLY WORKS SOMETIMES, WHY?
          mParent.interrupt();
}

EJP wrote:
I'm not convinced about that. The wording in join() suggests that, but the wording in interrupt() definitely does not.Thread.join() doesn't really provide much in the way of details, but Object.wait() does:
"throws InterruptedException - if any thread interrupted the current thread +before+ or while the current thread was waiting for a notification. The interrupted status of the current thread is cleared when this exception is thrown."
every jdk method i've used which throws InterruptedException will always throw if entered while a thread is currently interrupted. admitted, i rarely use Thread.join(), so it's possible that method could be different. however, that makes the thread interruption far less useful if it's required to hit the thread while it's already paused.
a simple test with Thread.sleep() confirms my expected behavior (sleep will throw):
Thread.currentThread().interrupt();
Thread.sleep(1000L);

Replacement for PhaseListener in RAP 3.0 - execute code on the UI thread

Hello,
we've used a PhaseListener to open/close a database connection for each request.
The database connection is tied to the current UI thread.
Do you have any suggestion how to realize this without using a phase listener in RAP 3.0?
I've tried to use a MessageFilter but the handleMessage method is not executed on the UI thread.
Thank you,
Ken

Hi Ralf,
thank you for the explanation.
We actually do not open a connection for each request. We just start a "unit of work" for the current thread that is able to track the database connections that are created on demand. This unit of work (and hence the underlying connections) is closed after a request.
Now the problem is that we need to execute the code that starts and stops the unit of work within the UI thread. This is due to the fact that our model objects (that are displayed by JFace viewers for example) are bound to an entity manager that requires an active unit of work for the current thread to open an underlying database connection.
I don't see any other solutions as using a phase listener for the start and stop events of the UI thread or starting/stopping the unit of work for any individual interaction with the model objects. It is practically impossible to implement the latter in a clean way.
Any comments or suggestions are welcome.
Best regards,
Ken

The background thread running lazy writer encountered an I/O error

Hi I have a test server which has thrown the following error
File system error: A system error occurred while attempting to read or write to a file store. The system might be under memory pressure or low on disk space. Physical file: \\?\F:\MSAS11.DEPLOYAS\OLAP\Data\Prod_KCube.0.db\DIM Flags And Types.0.dim\3.Flag
Types Key.khstore. Logical file: . GetLastError code: 8. File system error: The background thread running lazy writer encountered an I/O error. Physical file: \\?\F:\MSAS11.DEPLOYAS\OLAP\Data\Prod_KCube.0.db\DIM Flags And Types.0.dim\3.Flag Types Key.khstore.
Logical file: . Errors in the OLAP storage engine: An error occurred while processing the 'Facts' partition of the 'Main Facts' measure group for the 'Prod_Cube' cube from the Prod_KCube database.
The cube sits on a not very well maintained server which is used by various users (it is a test server) with the following specs
Intel(R) Xenon(R) CPU x5690 @3.47GHz
24GB Ram
64 Bit operating system.
The Cube data and logs are on separate drives and have plenty data but the C drive (where SQL Server is installed) only has3.5Gb of space left.
It's a fairly big cube and I've managed to get it running by processing dimensions and facts bit by bit but errors when processed all together.
What could be causing the errors above?

Hi aivoryuk,
According to your description, you get the lazy writing error when processing partitions. Right?
In this scenario, the issue may cause by low memory for SSAS and lack of disk space. Please consider configure
Server Properties (Memory Page) and increase
memory setting for SSAS. If the .cub file is located in C drive, please reserve more disk space.
Please refer to a similar thread below:
https://social.msdn.microsoft.com/Forums/sqlserver/en-US/21bf84c5-f89a-464a-a5f1-2649fae5eb1e/while-processing-large-cubes-various-file-system-errors-the-background-thread-running-lazy-writer?forum=sqlanalysisservices
Best Regards,
Simon Hou
TechNet Community Support

How can I use the same thread to display time in both JPanel & status bar

Hi everyone!
I'd like to ask for some assistance regarding the use of threads. I currently have an application that displays the current time, date & day on three separate JLabels on a JPanel by means of a thread class that I created and it's working fine.
I wonder how would I be able to use the same thread in displaying the current time, date & day in the status bar of my JFrame. I'd like to be able to display the date & time in the JPanel and JFrame synchronously. I am developing my application in Netbeans 4.1 so I was able to add a status bar in just a few clicks and codes.
I hope somebody would be able to help me on this one. A simple sample code would be greatly appreciated.
Thanks in advance!

As you're using Swing, using threads directly just for this kind of purpose would be silly. You might as well use javax.swing.Timer, which has done a lot of the work for you already.
You would do it something like this...
    ActionListener timerUpdater = new ActionListener() {
        public void actionPerformed(ActionEvent evt) {
            // DateFormat would be better, but this is an example.
            String timeString = new Date().toString();
            statusBar.setText(timeString);
            someOtherLabel.setText(timeString);
    new Timer(1000, timerUpdater).start();That code will update the time once a second. If you aren't going to display seconds, you might as well increase the delay.
The advantage of using a timer over using an explicit thread, is that multiple Swing timers will share a single thread. This way you don't blow out your thread count. :-)

Multiple threads but they are using the same thread ID

I'm a newbie in Java programming. I have the following codes, please take a look and tell me what wrong with my codes: server side written in Java, client side written in C. Please help me out, thanks for your time.
Here is my problem: why my server program assigns the same thread ID for both threads???
.Server side: start server program
.Client side: set auto startup in /etc/rc.local file in a different machine, so whenever this machine boots up, the client program will start automatically.
==> here is the result with 2 clients, why they always come up the same thread ID ????????
Waiting for client ...
Server thread 1024 running
Waiting for client ...
Server thread 1024 running
But if I do like this, they all work fine:
.Server side: start server program
.Client side: telnet or ssh to each machine, start the client program
==> here is the result:
Waiting for client ...
Server thread 1024 running
Waiting for client ...
Server thread 1025 running
server.java file:
import java.io.*;
import java.net.*;
import java.awt.*;
import java.util.Hashtable;
import java.util.Enumeration;
import java.util.regex.Pattern;
import java.util.Date;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.text.*;
public class Server extends Frame implements Runnable
private ServerThread clients[] = new ServerThread[50];
private ServerSocket server = null;
private Thread thread = null;
private int clientCount = 0;
//some variables over here
public Server(int port)
//GUI stuffs here
//network stuff
try
System.out.println("Binding to port " + port + ", please wait ...");
server = new ServerSocket(port);
System.out.println("Server started: " + server);
start();
catch(IOException ioe)
System.out.println("Can not bind to port " + port + ": " + ioe.getMessage());
public boolean action(Event e, Object arg)
//do something
return true;
public synchronized void handle(int ID, String input)
//do something
public synchronized void remove(int ID)
int pos = findClient(ID);
if (pos >= 0)
//remove a client
ServerThread toTerminate = clients[pos];
System.out.println("Removing client thread " + ID + " at " + pos);
if (pos < clientCount-1)
for (int i = pos+1; i < clientCount; i++)
clients[i-1] = clients;
clientCount--;
try
{ toTerminate.close(); }
catch(IOException ioe)
{ System.out.println("Error closing thread: " + ioe); }
toTerminate.stop();
private void addThread(Socket socket)
if (clientCount < clients.length)
clients[clientCount] = new ServerThread(this, socket);
try
clients[clientCount].open();
clients[clientCount].start();
clientCount++;
catch(IOException ioe)
System.out.println("Error opening thread: " + ioe);
else
System.out.println("Client refused: maximum " + clients.length + " reached.");
public void run()
while (thread != null)
try
{ System.out.println("Waiting for a client ...");
addThread(server.accept());
catch(IOException ioe)
System.out.println("Server accept error: " + ioe); stop();
public void start()
if(thread == null)
thread = new Thread(this);
thread.start();
public void stop()
if(thread != null)
thread.stop();
thread = null;
private int findClient(int ID)
for (int i = 0; i < clientCount; i++)
if (clients[i].getID() == ID)
return i;
return -1;
public static void main(String args[])
Frame server = new Server(1500);
server.setSize(650,400);
server.setLocation(100,100);
server.setVisible(true);
ServerThread.java file
import java.net.*;
import java.io.*;
import java.lang.*;
public class ServerThread extends Thread
private Server server = null;
private Socket socket = null;
private int ID = -1;
InputStreamReader objInStreamReader = null;
BufferedReader objInBuffer = null;
PrintWriter objOutStream = null;
public ServerThread(Server server, Socket socket)
super();
server = _server;
socket = _socket;
ID = socket.getPort();
public void send(String msg)
objOutStream.write(msg);
objOutStream.flush();
public int getID()
return ID;
public void run()
System.out.println("Server thread " + ID + " running");
while(true)
try{
server.handle(ID,objInBuffer.readLine());
catch(IOException ioe)
System.out.println(ID + "Error reading: " + ioe.getMessage());
//remove a thread ID
server.remove(ID);
stop();
public void open() throws IOException
//---Set up streams---
objInStreamReader = new InputStreamReader(socket.getInputStream());
objInBuffer = new BufferedReader(objInStreamReader);
objOutStream = new PrintWriter(socket.getOutputStream(), true);
public void close() throws IOException
if(socket != null) socket.close();
if(objInStreamReader != null) objInStreamReader.close();
if(objOutStream !=null) objOutStream.close();
if(objInBuffer !=null) objInBuffer.close();
And client.c file
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h> /* close */
#include <time.h>
#define SERVER_PORT 1500
#define MAX_MSG 100
//global variables
long lines = 0;
int sd = 0;
char command[100];
time_t t1,t2;
double timetest = 0.00;
int main (int argc, char *argv[])
int rc, i = 0, j = 0;
struct sockaddr_in localAddr, servAddr;
struct hostent *h;
char buf[100];
FILE *fp;
h = gethostbyname(argv[1]);
if(h==NULL) {
printf("unknown host '%s'\n",argv[1]);
exit(1);
servAddr.sin_family = h->h_addrtype;
memcpy((char *) &servAddr.sin_addr.s_addr, h->h_addr_list[0], h->h_length);
servAddr.sin_port = htons(SERVER_PORT);
/* create socket */
sd = socket(AF_INET, SOCK_STREAM, 0);
if(sd<0) {
perror("cannot open socket ");
exit(1);
/* bind any port number */
localAddr.sin_family = AF_INET;
localAddr.sin_addr.s_addr = htonl(INADDR_ANY);
localAddr.sin_port = htons(0);
rc = bind(sd, (struct sockaddr *) &localAddr, sizeof(localAddr));
if(rc<0) {
printf("%s: cannot bind port TCP %u\n",argv[1],SERVER_PORT);
perror("error ");
exit(1);
/* connect to server */
rc = connect(sd, (struct sockaddr *) &servAddr, sizeof(servAddr));
if(rc<0) {
perror("cannot connect ");
exit(1);
//send register message
rc = send(sd, "register\n", strlen("register\n"), 0);
//if can't send
if(rc < 0)
close(sd);
exit(1);
//wait here until get the flag from server
while(1)
buf[0] = '\0';
rc = recv(sd,buf,MAX_MSG-1,0);
if(rc < 0)
perror("receive error\n");
close(sd);
exit(1);
buf[rc] = '\0';
if(strcmp(buf,"autoplay")==0)
//do something here
else if(strcmp(buf,"exit")==0)
printf("exiting now ....\n");
close(sd);
exit(1);
return 0;

Yes......I do so all the time.

Is there a way to figure out what the current thread is?

I've got the following snippet of code:
// create a new thread. If the current thread is not this new thread, return
Thread CountDownThread = new Thread("CountDownThread");
CountDownThread.start();
if (/*CURRENT THREAD*/.getName() != CountDownThread.getName()) {
     System.out.println ("I'm not CountDownThread. I'm leaving.");
     return;
// current thread should be new thread. Therefore start the countdown
CurrTime = InitTime;
while(CurrTime.charAt(0) != '-') {      // go until current time is negative
     CurrTime = C.countDown();       // returns the current time based on the difference between the initial and elapsed time
     setText(CurrTime);                   // display current time in JLabel
C.reset();
setText(C.getCurrTime());What I'm trying to do is get a clock (C) to count down and display the time remaining in a JLabel (this snippet is taken from a method within that very JLabel which I'm extending from javax.swing.JLabel). While it's counting down, I'd like for the program to go off and do other things. Therefore, I'm trying to create a new thread that carries out the task of counting down while the original/main thread moves on to do other things.
Please have a look at the above code and tell me if I'm on the right track. The one thing I don't know how to do is figure out how to tell which thread the current thread is. I'm assuming that both the new thread and original/main one will execute the if statement, the new one after it returns from start() (which I haven't defined). The original/main one will detect that it is not the new thread and return, whereas the new thread will and go on to the while loop. In the while loop, it will count down the clock until it reaches 0, after which point it will reset it and die.
If I'm on the right track, all I need to know is how to detect which thread is currently executing. If I'm not on the right track, what would be the best way to do this?

What? No! No Thread terminates on the return of start(). Those two events are unrelated!Uh... I think you misunderstood what I said.
I didn't say that CountDownThread terminates upon returning from start() (which is what it sounds like you interpreted from me); I said that the thread that CountDownThread creates terminates once CountDownThread returns from start() (i.e. like any other local variable/object). This, of course, assumes that CountDownThread has a Runnable object on which to call its run() method (am I right?), in which case my code above doesn't create a new thread at all (i.e. CountDownThread.start() is executed within the main/original thread) - am I right?
No, run() doesn't call start()! That would be stupid.Again, you misunderstood. I shouldn't need to explain this one. A simple reference to an ordinary dictionary on the words 'former' and 'latter' should suffice :)
Anyway, all joking aside, I have now improved my code and it works! Here's what it looks like:
ClockJLabel.java
package MazeMania.clock;
public class ClockJLabel extends javax.swing.JLabel {
private Clock C;
private ClockJLabelsRunnable CJLR;
public ClockJLabel() {
C = new Clock();
CJLR = new ClockJLabelsRunnable();
setText(C.getCurrTime()); // should be 00:00:00:00
setHorizontalAlignment(javax.swing.SwingConstants.CENTER);
// need to figure out how to set the size so that it sticks
setForeground(new java.awt.Color(255, 0, 0));
setBackground(new java.awt.Color(0, 0, 0));
setOpaque(true);
// starts the clock counting up indefinitely from 0
public void start() {
(new Thread(new Runnable() {
    public void run() {
     while(true) setText(C.getElapsedTime());
   })).start();
//System.out.println("Started clock...");
// starts the clock counting down from an initial time and runs this count down in a separate thread
public void countDown(String InitTime) {
// initialize the clock
try {C.initClock(InitTime);}
catch(java.text.ParseException PE) {
   System.out.println(PE.getMessage());
// initialize JLabel's display
setText(C.getCurrTime());
// prepare Runnable and give it to new Thread. New Thread starts count down.
CJLR.task = CJLR.COUNTDOWN;
CJLR.CJL = this;
Thread CountDownThread = new Thread(CJLR);
CountDownThread.start();
public Clock getClock() {
return C;
}ClockJLabelsRunnable
package MazeMania.clock;
import java.lang.Runnable;
class ClockJLabelsRunnable implements Runnable {
public static int COUNTDOWN = 1;
public static int COUNTUP = 2;
// NOTE: this Runnable doesn't test for the proper setting of these variables
public int task = 0;
public ClockJLabel CJL = null;
public void run() {
Clock C = CJL.getClock();
while(C.countDown().charAt(0) != '-') {CJL.setText(C.getCurrTime());}
C.reset();
CJL.setText(C.getCurrTime());

I have a doubt about The Single-Thread Rule

The [url http://java.sun.com/docs/books/tutorial/uiswing/overview/threads.html#rule]Single Thread Rule states:
Rule: Once a Swing component has been realized, all code that might affect or depend on the state of that component should be executed in the event-dispatching thread.
I began to wonder about this because so much code seems to work just fine when it isn't executed in the event dispatching thread. Why are there exceptions? I went looking for some code which acted differently when executed on the event thread than when it was not. I found this
http://forum.java.sun.com/thread.jsp?forum=57&thread=410423&message=1803725#1803725
Now I started wondering why this was the case. What I found was that DefaultCaret adds a document listener to the document of the JTextComponent. In this listener, the insertUpdate() method specifically tests if it is running on the event dispatch thread and if it is, it updates the caret position.public void insertUpdate(DocumentEvent e) {
    if (async || SwingUtilities.isEventDispatchThread()) {
        // ... update the caret position ...
}I then copied the code from DefaultCaret and made a MyCaret. I needed to tweek the code a little bit, but it ran. I removed the event thread test. It worked outside the event thread. There was a small difference in the results though. The textarea did not scroll all the way to the bottom. Almost, but not quite. I didn't test enough to make sure this was the only problem, but there was at least one problem.
Now I started think about why this would be. The thought crossed my mind that the order of the events which were posted to the event queue were probably important. Sun found bugs when components were updated out of the event thread, so they essentially ignored events which weren't on the event thread and created the The Single-Thread Rule.
A few days pass. I'm starting to wonder if Sun could have done a better job making Swing components thread safe. I also don't know that this specific case I found was the rule or the exception to the rule. But without insight into the design philosopy of Swing, I would have to examine all their components and see how they have written them and see if I can come up with a better design. That sound like a lot of work. Especially without getting paid for it.
But wait a second, all you have to do is call the append() method of JTextArea on the event thread. If that is the case, why didn't they write the freakin component that way? Well, I'll try itclass MyTextArea extends JTextArea {
public MyTextArea(int rows, int columns) { super(rows,columns); }
public void append(final String text) {
    if (SwingUtilities.isEventDispatchThread()) super.append(text);
    else {
      SwingUtilities.invokeLater(new Runnable() {
        public void run() { myAppend(text); }
private void myAppend(String text) { super.append(text); }
}I change [url http://forum.java.sun.com/thread.jsp?forum=57&thread=410423&message=1803725#1803725]camickr's code to use a MyTextArea and it works fine without calling from the event thread. I've essentially moved The Single-Thread Rule to the component itself rather than relying on each and every one of the [url http://www.aboutlegacycoding.com/default.htm?AURL=%2FSurveys%2FSurvey6intro%2Easp]2.5 million Java programmers worldwide to use SwingUtilities.invaokeLater().
Now for my question...
Why didn't Sun do this?

Swing is slow enough as it is. Lets not make it slower
just
because dense "programmers" don't know what they are
doing.I agree with you in defending the current model, but aren't you a bit harsh there?!? ;-)
Well, there are a number of not-so-dense programmers that expect such high-level components to be thread-safe. The question is worth asking whether Sun intentionally favor the explicit thread management for performance reasons, or whether this was an oversight.
I'd go for the former (intentional) : indeed any GUI toolkit is inherently thread-based; there is always a distinction between the graphical thread(s) and the application threads - and the programmer always has to manage explicit thread creation to handle long-running event handlers without blocking the event dispatching thread. Extending thread concerns to the updating of components is therefore not a big move.
So it seems fair that a core GUI toolkit does not hide thread issues (though to the best of my knowledge there is no such limitation in updating AWT components), or at least that's what Sun deemed.
An ease-of-use-focused toolkit wrapping the core toolkit for thread-safety can be provided as a third-party product. Though I agree that wrapping the dozens of existing widgets and hundreds of methods is cumbersome - and the lack of such products probably shows it would have a low added value to trained developpers.
Because your way is an extra method call and if
statement, neither of which is necessary if you already know you
are in the correct thread. Now count the number of methods
which will need to be changed (and add up the extra cost).Indeed it's quite common to update several properties of several widgets in one bulk (when user clicks "OK", add a row to the table, change the title of the window, update status bar, re-enable all buttons, change some color,...).
In this case explicit thread management doesn't spare one if but a dozen of redundant ifs!
Note that there could have been if-less ways to cope for thread safety, such as creating a copy of the component's model when a change is made to a component, and switching the model only before paint() is called in the event-dispatching - of course coalescing all changes into the same "updated" model until paint() is called.
But this would trade ease of use for redundant memory consumption, especially for some components with potentially huge models (JTree, JTable, JTextArea,...). And Swing appears to be already quite memory-greedy!

Calling a delegate on the UI thread from a work thread inside a child class.

Hi All,
I've run into a snag developing a WPF multithreaded app where I need to call a method on the UI thread from my work thread, where the work thread is running a different class.
Currently I am trying to use a delegate and an event in the 2nd class to call a method in the 1st class on the UI thread. This so far is not working as because the 2nd class is running in its own thread, it causes a runtime error when attempting to call
the event.
I've seen lots of solutions referring to using the dispatcher to solve this by invoking the code, however my work thread is running a different class than my UI thread, so it seems the dispatcher is not available?
Below is as simplified an example as I can make of what I am trying to achieve. Currently the below code results in a "The calling thread cannot access this object because a different thread owns it." exception at runtime.
The XAML side of this just produces a button connected to startThread2_Click() and a label which is then intended to be updated by the 2nd thread calling the updateLabelThreaded() function in the first thread when the button is clicked.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Windows.Threading;
using System.Threading;
namespace multithreadtest
public delegate void runInParent();
public partial class MainWindow : Window
public MainWindow()
InitializeComponent();
threadUpdateLabel.Content = "Thread 1";
private void startThread2_Click(object sender, RoutedEventArgs e)
thread2Class _Thread2 = new thread2Class();
_Thread2.runInParentEvent += new runInParent(updateLabelThreaded);
Thread thread = new Thread(new ThreadStart(_Thread2.threadedTestFunction));
thread.Start();
public void updateLabelThreaded()
threadUpdateLabel.Content = "Thread 2 called me!";
public class thread2Class
public event runInParent runInParentEvent;
public void threadedTestFunction()
if (runInParentEvent != null)
runInParentEvent();
I'm unfortunately not very experienced with c# so I may well be going the complete wrong way about what I'm trying to do. In the larger application I am writing, fundamentally I just need to be able to call a codeblock in the UI thread when I'm in a different
class on another thread (I am updating many different items on the UI thread when the work thread has performed certain steps, so ideally I want to keep as much UI code as possible out of the work thread. The work threads logic is also rather complicated as
I am working with both a webAPI and a MySQL server, so keeping it all in its own class would be ideal)
If a more thorough explanation of what I am trying to achieve would help please let me know.
Any help with either solving the above problem, or suggestions for alternative ways I could get the class in the UI thread to do something when prompted by the 2nd class in the 2nd thread would be appreciated.
Thanks :)

If I follow the explanation, I think you can use MVVM Light messenger.
You can install it using NuGet.
Search on mvvm light libraries only.
You right click solution in solution explorer and choose manage nugget...
So long as you're not accessing ui stuff on these other threads.
using GalaSoft.MvvmLight.Messaging;
namespace wpf_Tester
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
public MainWindow()
InitializeComponent();
Messenger.Default.Register<String>(this, (action) => ReceiveString(action));
private void ReceiveString(string msg)
MessageBox.Show(msg);
Dispatcher.BeginInvoke((Action)delegate()
tb.Text = msg;
private void Button_Click(object sender, RoutedEventArgs e)
Task.Factory.StartNew(() => {
Messenger.Default.Send<String>("Hello World");
What the above does is start up a new thread - that startnew does that.
It sends of message of type string which the main window has subscribed to....it gets that and puts up a message box.
The message is sent from the window to the window in that but this will work across any classes in a solution.
Note that the receive acts on whichever thread the message is sent from.
I would usually be altering properties of a viewmodel with such code which have no thread affinity.
If you're then going to directly access properties of ui elements then you need to use Dispatcher.BeginInvoke to get back to the UI thread.
I do that with an anonymous action in that bit of code but you can call a method or whatever instead if your logic is more complicated or you need it to be re-usable.
http://social.technet.microsoft.com/wiki/contents/articles/26070.aspx
Hope that helps.
Technet articles: Uneventful MVVM;
All my Technet Articles

Facebook like button is not working, I have used the muse widget and created code from facebook. Does anyone know how to get this to work?

Facebook like button is not working, I have used the muse widget and created code from facebook. Does anyone know how to get this to work?

Hi connally25,
Below is a link to a video tutorial on how to add a Facebook Log button, please check if you have followed the same steps to add the video.
http://tv.adobe.com/watch/learn-adobe-muse-cc/adding-a-facebook-like-button/
If you have followed the steps correctly and the button still does not work; here is a link to a forum thread which might help solving the issue:
Facebook Follow Widget not working
Regards
Sonam

How to terminate a java thread from c++ code?

Hi,
I made a screensaver which loads a jvm, forks a thread running a java class, wait until user's action(i.e. mouse move/click keyboard input), then terminate the java thread.
However, I met a problem, How to terminate a running java thread from c++ code?
Here is my code, but it does not work: (even after the terminate is called, jvm throws an error)
JNIEnv* env;
JavaVM* jvm;
HANDLE hThread; //handle for the startThread
unsigned __stdcall startThread(void *arg)
     jclass cls;
     jmethodID mainId;
     jint          res;
     int threadNum = (int)arg;
     res = jvm->AttachCurrentThread((void**)&env, NULL);
cls = env->FindClass( MAIN_CLASS);
     mainId = env->GetStaticMethodID(cls, "main", "([Ljava/lang/String;)V");
     // setup the parameters to pass to main()
     jstring str;
     jobjectArray args;
     int i=0;
     args = env->NewObjectArray(1, env->FindClass("java/lang/String"), 0); //only one input parameters
     str = env->NewStringUTF("localhost");
     env->SetObjectArrayElement(args, 0, str);
     env->CallStaticVoidMethod(cls, mainId, args); // call main()
     if (env->ExceptionOccurred()) {
               env->ExceptionDescribe();
     return TRUE;
Here is the main method:
First create the jvm and load the thread. then tries to terminate the thread, but failed here
switch (msg)
{ case WM_CREATE:
          JavaVMOption options[NUMBEROFOPTIONS];
          JavaVMInitArgs vmargs;
          jint rc;
          vmargs.version = JNI_VERSION_1_4; /* version 1.4 */
          vmargs.options = options;
          vmargs.nOptions = NUMBEROFOPTIONS;
          vmargs.ignoreUnrecognized = JNI_FALSE;
          rc=JNI_CreateJavaVM( &jvm, (void **)&env, &vmargs ); /* create JVM */
          /* We pass the thread number as the argument to the invoked thread */
          unsigned int threadId = -1;
          // to initialize a thread-safe C runtime library
          hThread = (HANDLE)_beginthreadex(NULL, 0, &startThread, NULL, 0, &threadId );
} break;
case (WM_DESTROY):
          CloseHandle( hThread );
          jvm->DestroyJavaVM(); /* kill JVM */
          Debug("Destroy Java Virtual Machine\n");
}break;
Note, after the thread "startThread" runs, it has an infinite loop and will not terminate, until the user clicks to terminate.(I didn't call jvm->DetachCurrentThread();_endthreadex(0); in the "startThread" because the java thread will not terminate by itself)
Thus, the only way to terminate the thread is to call closehandle(hthread) in the main thread, which may cause jvm to throw an error.
Do you know how to terminate a java thread safely???
Thanks a lot

Assuming that your java thread is in a loop of some kind. Such as
int i=1; /* I tried using a boolean, I just could not get my C++ env, to change this value. So i decided to use an int */
run {
while(i)
isdfjsdfj
void seti()
i=0
So, B/4, i call destroyVM in my C++ code, i call this seti(). so the loop terminates, therefore my thread finishes executing and ends.
Hope this helps
tola.

How to hold the main thread, till response is received from the server?

I have a program in which the GUI client(View program in Swings) sends a request to server (Manager program) , and waits for the response from Manager.
The method used is waitForResponse() as follows
<code>
private void waitForResponse()
m_blWaitFlag=true;
//after response from manager m_blWait flag is set to false.
while (m_blWaitFlag)
try
Thread.sleep(500);
}catch(Exception r_ex)
</code>
And in notifyResponse() method, the wait flag is set to false
as in,
<code>
public void notifyResponse(VcvResponse r_objResponse)
m_blWaitFlag = false; //this line makes the thread to come out of the wait mode.
</code>
When I click a menu item, this request is sent and there is a wait for a response from manager.
The problem is , this kind of waiting makes the system slow, and grey patches are seen immediately after clicking a menu item.
Are there other ways of waiting??
Thanks in advance

When I click a menu item, this request is sent and there is a wait for a response from manager.This means you are using the GUI thread to send the request.
The problem is , this kind of waiting makes the system slow, and grey patches are seen immediately after clicking a menu item.This means the GUI thread is waiting for the response. No GUI updates can occur while it is waiting.
Are there other ways of waiting??Use another thread. e.g the main as you suggested. If you are using a callback, why do you have a thread waiting at all? WHy not do the things you would do when a response comes back in the call back?

How do I access objects from the original Thread?

I have this simple JApplet that just makes a circle bounce around the screen. Here it is:
import java.awt.Color;
import javax.swing.JApplet;
import java.awt.Graphics;
import java.awt.event.MouseListener;
import java.awt.event.MouseEvent;
public class TestApplet3 extends JApplet implements MouseListener {
    private int lastX;          // x coordinate of circle
    private int lastY;          // y coordinate of circle
    private int d = 15;          // diameter of circle
    public void paint(Graphics g) {
    public void init() {
        addMouseListener(this);
    public void mouseClicked(MouseEvent event) {
        Graphics gx = this.getGraphics();
        for (int x = 0, y = 0, count = 0, horiz = 2, vert = 2, k = 2; count < 1000; x = x + horiz, y = y + vert, count++) {
            if ((x + d) >= 350) {
                horiz = -horiz;
            if ((x <= 0) && (horiz < 0)) {
                horiz = -horiz;
            if ((y + d) >= 200) {
                vert = -vert;
            if ((y <= 0) && (vert < 0)) {
                vert = -vert;
            gx.setColor(Color.WHITE);
            gx.fillOval(lastX, lastY, d, d);
            gx.setColor(Color.RED);
            lastX = x;
            lastY = y;
            gx.fillOval(lastX, lastY, d, d);
            try {
                Thread.sleep(20);
            } catch (Exception ex) {
                System.out.println(ex.getMessage());
    public void mouseEntered(MouseEvent event) {
    public void mouseExited(MouseEvent event) {
    public void mousePressed(MouseEvent event) {
    public void mouseReleased(MouseEvent event) {
}But now I'd like to change it so that when the mouse is clicked a new Thread is spawned to run the code within the mouseClicked method..... this will allow multiple circles to bounce around and will also keep the applet responsive to new mouse clicks... so I've tried changing it below:
* To change this template, choose Tools | Templates
* and open the template in the editor.
package runninggraph;
* @author epuknol
import java.awt.Color;
import javax.swing.JApplet;
import java.awt.Graphics;
import java.awt.event.MouseListener;
import java.awt.event.MouseEvent;
public class TestApplet3 extends JApplet implements MouseListener, Runnable {
    private int lastX;          // x coordinate of circle
    private int lastY;          // y coordinate of circle
    private int d = 15;          // diameter of circle
    public void paint(Graphics g) {
    public void init() {
        addMouseListener(this);
    public void run() {
        Graphics gx = this.getGraphics();
        for (int x = 0, y = 0, count = 0, horiz = 2, vert = 2, k = 2; count < 1000; x = x + horiz, y = y + vert, count++) {
            if ((x + d) >= 350) {
                horiz = -horiz;
            if ((x <= 0) && (horiz < 0)) {
                horiz = -horiz;
            if ((y + d) >= 200) {
                vert = -vert;
            if ((y <= 0) && (vert < 0)) {
                vert = -vert;
            gx.setColor(Color.WHITE);
            gx.fillOval(lastX, lastY, d, d);
            gx.setColor(Color.RED);
            lastX = x;
            lastY = y;
            gx.fillOval(lastX, lastY, d, d);
            try {
                Thread.sleep(20);
            } catch (Exception ex) {
                System.out.println(ex.getMessage());
    public void mouseClicked(MouseEvent event) {
        (new Thread(new TestApplet())).start();
    public void mouseEntered(MouseEvent event) {
    public void mouseExited(MouseEvent event) {
    public void mousePressed(MouseEvent event) {
    public void mouseReleased(MouseEvent event) {
}but this doesn't work - I think because the this.getGraphics() doesn't refer back to the same object ..... I've tried some other things too - like defining the Graphics gx as a class variable and initializing it before spawning the new Thread ... but I can't access gx using that technique either.
Can somebody please help me get where I'm trying to go?
Thanks.

Aw heck, got bored. For instance, this draws a bunch of balls without a direct call to Thread anything:
BouncingCircles.java
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JPanel;
import javax.swing.Timer;
* creates a JPanel that draws bouncing circles within it.
* @author Pete
public class BouncingCircles {
private static final int DELAY = 15;
private static final int DIAMETER = 15;
private static final int DELTA = 5;
List<Ball> ballList = new ArrayList<Ball>(); // list of all balls
private JPanel mainPanel = new JPanel() {
    @Override
    protected void paintComponent(Graphics g) {
      super.paintComponent(g);
      myPaint(g);
// Swing Timer that tells the balls to move and tells the JPanel to then draw them
private Timer sTimer = new Timer(DELAY, new ActionListener() {
    public void actionPerformed(ActionEvent e) {
      timerAction(e);
public BouncingCircles() {
    mainPanel.setPreferredSize(new Dimension(400, 400));
    mainPanel.addMouseListener(new MouseAdapter() {
      @Override
      // add new ball with each mouse press
      public void mousePressed(MouseEvent e) {
        ballList.add(new Ball(e.getPoint(), new Point(DELTA, DELTA)));
    sTimer.start();
public JPanel getPanel() {
    return mainPanel;
private void timerAction(ActionEvent e) {
    Dimension d = mainPanel.getSize();
    for (Ball ball : ballList) {
      if (ball.getPoint().x < 0) {
        ball.setXDirectionRight(true);
      } else if (ball.getPoint().x + DIAMETER > d.width) {
        ball.setXDirectionRight(false);
      if (ball.getPoint().y < 0) {
        ball.setYDirectionDown(true);
      } else if (ball.getPoint().y + DIAMETER > d.height) {
        ball.setYDirectionDown(false);
      ball.increment();
    mainPanel.repaint();
   * paintComponent method draws all balls in List
   * @param g
private void myPaint(Graphics g) {
    g.setColor(Color.red);
    Graphics2D g2d = (Graphics2D) g;
    RenderingHints rh = new RenderingHints(RenderingHints.KEY_ANTIALIASING,
        RenderingHints.VALUE_ANTIALIAS_ON);
    g2d.setRenderingHints(rh);
    for (Ball ball : ballList) {
      g.fillOval(ball.getPoint().x, ball.getPoint().y, DIAMETER, DIAMETER);
private class Ball {
    private Point point = new Point();
    private Point velocity = new Point();
    public Ball(Point point, Point velocity) {
      this.point = point;
      this.velocity = velocity;
    public Point getPoint() {
      return point;
    public Point getVelocity() {
      return velocity;
    public void increment() {
      point = new Point(point.x + velocity.x, point.y + velocity.y);
    public void setXDirectionRight(boolean right) {
      int newVelocityX = Math.abs(velocity.x);
      if (!right) {
        newVelocityX = -newVelocityX;
      velocity = new Point(newVelocityX, velocity.y);
    public void setYDirectionDown(boolean down) {
      int newVelocityY = Math.abs(velocity.y);
      if (!down) {
        newVelocityY = -newVelocityY;
      velocity = new Point(velocity.x, newVelocityY);
}And this displays the JPanel produced above in a standard JApplet.
BouncingCircApplet.java
import java.lang.reflect.InvocationTargetException;
import javax.swing.JApplet;
import javax.swing.SwingUtilities;
public class BouncingCircApplet extends JApplet {
@Override
public void init() {
    try {
      SwingUtilities.invokeAndWait(new Runnable() {
        public void run() {
          getContentPane().add(new BouncingCircles().getPanel());
    } catch (InterruptedException e) {
      e.printStackTrace();
    } catch (InvocationTargetException e) {
      e.printStackTrace();
}

Optimizing the # of threads to do code optimization

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