Wait and notify in servlets?
i am having a servlet , which is implementing wait and notify of java.lang.Object.
when serving it for single request , its waiting and working fine...
but for multiple requests its not serving properly. works one by one means the second request is waiting for finishing the first request just like SingleThreadModel (after finishing the first request only second request entering inside servlet)
please help me to solve this?
or is there any other way to call wait method without synchronized block??
Shynihan wrote:
or is there any other way to call wait method without synchronized block??No, and that's partly because if wait or notify is the only thing in the synchronized block then you probably aren't using them right. The problem is blocking the server thread. Servlet engines use a thread pool to execute transactions, when a new transaction comes in a thread is taken from the pool to run it, and there's usually a limited number of threads in the pool. If there's no threads left then the transaction will wait for another to finish.
If your servlets freeze up, then that's a thread gone from the pool.
And remeber the unlocking transaction may never arive. The client could go down at any time, leaving the server thread permanently hung.
You need to move this waiting to the client side. If the transaction cannot proceed then return a "come back later" response immediately. The client can then retry after a decent interval.
Similar Messages
-
A bug in wait and notify? -- help
Now I am engaged in a simulation project. The threads are all controlled by the controller program, that is, they are often blocked and unblocked by using wait and notify methods. However, when I was debugging my program, there were always some errors occurring and halting the simulation. And I found that the cause was that the threads sometimes might halt after having executed the wait or notify methods!!
Example,
in thread 1, it would be blocked by a wait method like:
synchronized(lock){
lock.wait();
System.out.println("Thread 1 go on.");
In thread 2, it would unblock thread 1 with the notify method:
synchrnoized(lock){
System.out.println("Thread 2 would notify the threads blocked on lock.");
lock.notifyAll();
System.out.println("Thread 2 go on.");
The simulation program controls the time to execute the thread 2. However, in debugging the program I often encountered the problem that thread 2 did notify thread 1 and thread would go on executing, but thread 2 would not go further. That is, the output is like:
Thread 2 would notify the threads blocked on lock.
Thread 1 go on.
But the String, "Thread 2 go on." would not be printed out.
It was so strange, and I repeated for tens of times, it always occurred here and there.
Is it a bug of java?There seems to be nothing wrong with this to me:
You should use better debugging messages. I couldn't read it the way you had it.
public class BugThread extends Thread
Object lock;
Notifier notifier;
public static void main(String[] arg)
for(int i = 0; i < 5; i ++)
Object lock = "lock " + i;
Notifier noti = new Notifier(lock);
BugThread bug = new BugThread(lock, noti);
bug.start();
noti.start();
public BugThread(Object lock, Notifier notifier)
this.lock = lock;
this.notifier = notifier;
public void run()
int i = 0;
while( i++ < 100)
synchronized(lock)
System.out.println("Bug thread: "
+ lock + " would block at Object: "
+ lock);
try
lock.wait();
catch(InterruptedException ex)
ex.printStackTrace();
System.out.println("Bug thread: "
+ lock + " unblocked at Object: "
+ lock);
notifier.stop();
class Notifier extends Thread
Object lock;
public Notifier(Object lock)
this.lock = lock;
public void run()
int i = 0;
while(true)
synchronized(lock)
System.out.println("Notifier: " + lock
+ " would notify Bugthread blocking at object: "
+ lock.toString() + ". time no." + i);
lock.notifyAll();
System.out.println("Notifier: " + lock
+ " notified bugthread. time no." + i);
System.out.println("Notifier: " + lock
+ " go on working. time no." + i);
i ++;
} -
Hi,
Who can give me a short java code segment to show the method wait and notify of the class Object.
I've already tryed as forlow:
try {
A a = new A();
a.wait() ;
catch (InterruptedException ex) {
ex.printStackTrace() ;
But a thread is always be thrown:
java.lang.IllegalMonitorStateException: current thread not owner
at java.lang.Object.wait(Native Method)
at java.lang.Object.wait(Object.java:420)
at A.main(A.java:34)
Who can tell which thread should be the owner thread? I did realize noly one thread there.
Thanks a million.The classic example is two threads, on adding items to a queue and one taking them off and processing them:
// consumer
Object item = null;
do {
synchronized(queue) {
if(queue.isEmpty())
queue.wait();
item = queue.remove(0);
// process item
} while(!Thread.currentThread.isInterrupted());
// producer
synchronized(queue) {
if(queue.isEmpty())
queue.notify();
queue.add(item);
}The use of synchronized blocks or methods is essential. They guard against conflicts and race conditions between different sections that change the same data. -
Why wait and notify kept in object class only
why wait and notify kept in object class only. is it maintain locks while doing wait and notify . please explain internals,
What do you mean in Object class "only"? If they're in Object, then they're in ALL classes.
They're in Object because any Object can serve as a lock.
For details of how to use them, see a Java threading tutorial such as http://java.sun.com/docs/books/tutorial/essential/threads/ -
Wait() and notify() or Semaphores with single permits?
Hi,
What's the difference between using wait(), notify() and single permitted Semaphores? Does using the latter affect the performance in massively multi-threaded environments?I wrote a very simple program to simulate a Queue like structure, and a Producer with a Consumer which both are running in separate threads. I changed the Queue class to hold only one value (It's not a queue any more, but the name didn't change). Then I used a boolean value, wait() and notify() methods of the Object class to ensure that every put() by the producer is followed by a get() by the consumer. Here's the Queue class code:
class Queue {
private int num;
private boolean valueSet = false;
synchronized void put(int n) {
while(valueSet) {
try {
wait();
} catch(InterruptedException err) {
System.out.println("put() interrupted.");
num = n;
valueSet = true;
notify();
System.out.println("Put: "+n);
synchronized int get() {
while(!valueSet) {
try {
wait();
} catch(InterruptedException err) {
System.out.println("get() interrupted.");
valueSet = false;
notify();
System.out.println("Got: "+num);
return num;
}Producer and Consumer classes simply repeat calling put() and get() methods respectively for a number of times. I also implemented all this by using Semaphores with single permits:
import java.util.concurrent.*;
class Queue {
private int num;
private final static Semaphore semCon = new Semaphore(0);
private final static Semaphore semPro = new Semaphore(1);
void put(int n) {
try {
semPro.acquire();
} catch(InterruptedException err) {
System.out.println("put() interrupted.");
num = n;
semCon.release();
System.out.println("Put: "+n);
int get() {
try {
semCon.acquire();
} catch(InterruptedException err) {
System.out.println("get() interrupted.");
semPro.release();
System.out.println("Got: "+num);
return num;
}Which one is better? Better in every aspect, such as performance, being maintainable, etc. I don't know whether it's a good idea to use Semaphores in these cases.
Thanks for your reply. -
I have a main that calls a drawing window. The user draws in the window and clicks a button when finished drawing. Then main then gets this image. I don't know how to call the getImage in the main ONLY after the user has clicked the button in the draw window, however. I've heard about wait and notify commands, but I don't know how to use them. Can anyone help me? Thanks.
Oh my... I'm not a java superstar. I'll post my code and maybe someone can help me. I tried running wait, but it says not thread owner or something weird.
Main:
public static void main (String [] args) throws IOException, InterruptedException, AWTException
Image image = null;
PaintArea pa = new PaintArea ();
pa.loadArea (pa);
//After screen capture
image = pa.getImage ();}PaintArea:
import java.awt.*;
import java.awt.event.*;
import java.io.*;
class PaintArea extends Frame
static int x, y;
static Image image;
Canvas canvas = null;
PaintArea ()
setSize (110, 160);
setVisible (true);
addWindowListener (new WindowAdapter ()
public void windowClosing (WindowEvent e)
hide ();
public void loadArea (PaintArea pa) throws InterruptedException
Button button = new Button ("Save");
Canvas drawArea = new Canvas ();
drawArea.setSize (100, 100);
canvas = drawArea;
pa.setLayout (new BorderLayout ());
pa.add (drawArea, BorderLayout.CENTER);
pa.add (button, BorderLayout.SOUTH);
pa.show ();
Graphics g = drawArea.getGraphics ();
final Graphics g2 = g;
final PaintArea pa2 = pa;
button.addActionListener (new ActionListener ()
public void actionPerformed (ActionEvent ae)
try
image = saveScreen (pa2);
catch (AWTException e)
System.err.println (e);
System.exit (1);
catch (InterruptedException ie)
System.err.println (ie);
System.exit (1);
drawArea.addMouseListener (new MouseAdapter ()
public void mousePressed (MouseEvent me)
x = me.getX ();
y = me.getY ();
g2.fillOval (x - 5, y - 5, 10, 10);
drawArea.addMouseMotionListener (new MouseMotionAdapter ()
public void mouseDragged (MouseEvent me)
x = me.getX ();
y = me.getY ();
g2.fillOval (x - 5, y - 5, 10, 10);
public Image saveScreen (PaintArea pa) throws AWTException
Image image = null;
try
image = createImage (new Robot ().createScreenCapture (pa.getDrawArea ().getBounds ()).getSource ());
catch (NullPointerException npe)
System.err.println (npe);
System.exit (1);
return image;
public Picture getImage ()
return image;
public Canvas getDrawArea ()
return canvas;
}Could someone please run that and try to make the pa.getImage() in the main happen only after the button in Paint Area is pressed? Thanks! -
IllegalMonitorStateException? wait() and notify()
Can someone tell me what's the deal with wait() and notify() methods? Like how to use them properly? Right now I have two threads, one being the main program and the other should run occationally when I need it... I try to get the second to wait() and second.notify() when I want to to run but IllegalMonitorStateException... so if you know a tutorial or you can explain it me it'll be great!
Thanks!This is a bit hard to answer without a code example. Have you gone through the tutorial available on this topic?
http://java.sun.com/docs/books/tutorial/essential/threads/index.html
If you have already looked at these, post your sample code (inside code tags, please - use the code button above) so others can read it and run it. -
Stuck with wait() and notify()
Hi,
I have a problem understanding synchronous access.
I have an object that should provide a list of data. The list is used later in my code, but it would increase performance to load it in a separate thread at the beginning. However it is possible that the list is not ready when the first other object tries to access the list.
I thought that this code should solve the problem
public class SingleObject implements Runnable {
ArrayList list;
public SingleObject(){
list = new ArrayList();
public synchronized void run() {
try {
makeALongProc(100);
} catch (InterruptedException e) {
e.printStackTrace();
notify();
private synchronized void makeALongProc(int size) throws InterruptedException{
System.out.println("...doing something ...");
Thread.sleep(5000);
for (int i = 0 ; i < size ; i++ ){
list.add(""+i);
System.out.println("finished!");
notifyAll();
public synchronized String getValueAt(int pos) throws InterruptedException{
wait();
return list.get(pos).toString();
public synchronized List getList() throws InterruptedException{
wait();
return list;
} The object is invoked by the following code.
public class ThreadProject {
* @param args
public static void main(String[] args) {
System.out.println("...starting thread...");
SingleObject so = new SingleObject();
Thread th = new Thread(so);
th.start();
try {
System.out.println("waiting ...");
List list = so.getList();
System.out.println("got list"+list.size());
String sso = so.getValueAt(5);
System.out.println(sso);
} catch (InterruptedException e) {
e.printStackTrace();
}Unfortunateley this is not doing what I have expected. Instead of calling the methodsso.getList() and so.getValueAt() it enters so.getList() and waits and waits....
Can anybody give my a clue or an explanation what I am doing wrong?
Regards
Sas
Message was edited by:
Poncho1975I have tried a little bit further.
I changed the following part:
public class SingleObject {
ArrayList list;
public SingleObject(){
list = new ArrayList();
public synchronized void makeALongProc(int size) throws InterruptedException{
System.out.println("...doing something ...");
Thread.sleep(5000);
for (int i = 0 ; i < size ; i++ ){
list.add(""+i);
System.out.println("finished!");
notify();
public synchronized String getValueAt(int pos) throws InterruptedException{
if (list==null || list.size()<=pos){
wait();
return list.get(pos).toString();
public synchronized List getList() throws InterruptedException{
if (list==null){
wait();
return list;
}and ...
public class ThreadProject {
* @param args
public static void main(String[] args) {
System.out.println("...starting thread...");
final SingleObject so = new SingleObject();
Thread th = new Thread(new Runnable(){
public synchronized void run() {
try {
so.makeALongProc(100);
} catch (InterruptedException e) {
e.printStackTrace();
th.start();
try {
System.out.println("waiting ...");
List list = so.getList();
System.out.println("got list"+list.size());
String sso = so.getValueAt(5);
System.out.println(sso);
} catch (InterruptedException e) {
e.printStackTrace();
}Now I am satisfied. Every call on a method from this object would lead to the situation, that either makeALongProc is called first or all other methods must wait until makeALongProc has been called once to fill the array.
However I suppose that accessing elements of a list with a synchronized object is not a good decision. I would rather take only the whole List and do all other access outside of the object.
Regards
Poncho -
The program tries to find the first socket connection. Theirs a wait and the notify call in the inner class seams to have to effect. Attach is the code to try out
import java.io.*;
import java.util.*;
import java.net.*;
import java.nio.channels.*;
* SocketSearch class to scan for an open socket from an array of sockets passed. <br>
* Inner class DetectSocketConnection tries to open the socket and assign hostname
* a value if successful. <br>
* The SocketSearch thread class is waiting to find the hostname or active DetectSocketConnection
* threads to be zero - i.e No hosts found
public class SocketSearch extends Thread {
private Object syncObject = new Object();
private String hostname = null;
private ThreadGroup threadGroup = new ThreadGroup("SOCKETS_CONNECT");
private ArrayList sockets = null;
* Inner class DetectSocketConnection to find an open socket. <br>
* It will assign the hostname a value if successful
private class DetectSocketConnection extends Thread {
private SocketChannel sc = null;
private String host = null;
private int port = -1;
public DetectSocketConnection(String host, int port) {
super(threadGroup, host);
this.host = host;
this.port = port;
System.out.println("DetectSocketConnection::syncObject = " + syncObject);
public void run() {
System.out.println("Scanning " + host + " at port number " + port);
synchronized(syncObject) {
try {
InetSocketAddress isa = new InetSocketAddress(InetAddress.getByName(host), port);
// Connect
sc = SocketChannel.open();
sc.connect(isa);
System.out.println("Found hostname: " + host + "!!!!!!!!!!!!!!!!!!!");
hostname = host;
catch (IOException e) {
System.err.println("DetectSocketConnection: " + e.toString());
finally {
// Make sure we close the channel (and hence the socket)
close();
System.out.println("DetectSocketSonnectio: notify()...");
syncObject.notify();
public void close() {
try {
if (sc != null) sc.close();
catch (IOException e) {
public SocketSearch() {
sockets = new ArrayList();
* Add socket to the sockets ArrayList to prepare to start the Socket Search
* @param host Socket hostname
* @param port Socket port number
public void addSocket(String host, int port) {
DetectSocketConnection detectSocket = new DetectSocketConnection(host, port);
sockets.add(detectSocket);
* SocketSearch start method to fire up the sockets threads to search for
public void start() {
super.start();
if (sockets != null) {
DetectSocketConnection[] arrSockets = (DetectSocketConnection[]) sockets.toArray(new DetectSocketConnection[0]);
for (int i = 0 ; i < arrSockets.length ; i++) {
arrSockets.start();
* Main code to do the socket search
public void run() {
try {
boolean loop = (sockets.size() > 0);
while (loop) {
synchronized(syncObject) {
System.out.println("SocketSearch.wait() => syncObject = " + syncObject);
syncObject.wait();
System.out.println("SocketSearch.wait() => syncObject = " + syncObject + ", finished...");
if (hostname != null) {
// use the hostname
// you could interrupt the threads now - its your choice
loop = false;
else {
System.out.println("Invalid hostname...");
ThreadGroup currentGroup = Thread.currentThread().getThreadGroup();
int numThreads = currentGroup.activeCount();
Thread[] listOfThreads = new Thread[numThreads];
currentGroup.enumerate(listOfThreads);
int activeThreads = 0;
for (int i = 0 ; i < numThreads ; i++) {
if (listOfThreads[i] instanceof DetectSocketConnection) {
activeThreads++;
System.out.println("activeThreads: " + activeThreads);
if (activeThreads == 0) {
// host name is NULL and active threads are finished
throw new UnknownHostException("Host not found.");
if (hostname != null) {
System.out.println("Found hostname: " + hostname);
// Do something here, use callback to maybe dispose ProgressDialog etc...
catch (UnknownHostException e) {
// Do something here, use callback to maybe dispose ProgressDialog etc...
System.err.println(e.toString());
catch (InterruptedException e) {
// Do something here, use callback to maybe dispose ProgressDialog etc...
System.err.println(e.toString());
* Test to find a socket from an array of test socket hosts
public static void main(String args[]) {
String[] yahooPOP3PossibleSettings = new String[] {
"yahoo.com",
"mail.yahoo.com",
"pop.yahoo.com",
"pop.mail.yahoo.com",
"pop3.yahoo.com"
int PORT_NUMBER = 110;
SocketSearch socketSearch = new SocketSearch();
for (int i = 0 ; i < yahooPOP3PossibleSettings.length ; i++) {
socketSearch.addSocket(yahooPOP3PossibleSettings[i], PORT_NUMBER);
socketSearch.start();Forget it. The Inner class was doing a wait and so was the main thread.
Not meant to put a wait in the main thread... -
Java compiler should check if wait() and notify()
wait(), notify(), and notifyAll() methods should be called within a critical section, but the Java compiler does not check for this. It is usually during running that an Exception is thrown when the methods was not called within a critical section.
To me, it seems that the compiler should check and enforce that wait(), notify() and notifyAll() be called within a critical section.I think I mis-understood you.
Yes, you are right to say that because callNotify() was called within a critical section at some time, and may be called from other non-critical sections, so the compiler does not have means to keep trace of the calling stack.
How about this:
Because critical sections are always marked by the synchronized keyword, the compiler can actually keep count of the synchronized word and its corresponding braces, then when a wait(), or notify(), or notifyAll() call is made at certain point, the compiler just check for the nested synchronized cunt number, if it is non-zero, it will be syntaxically correct.
Take the example of your code, I see that the proper point for
public class Test {
Object lock = new Object();
public void lockObject() {
synchronized (lock) {
callNotify(); // here the synchronized brace count is 1, so it is OK!
private void callNotify() {
lock.notify(); // here the synchronized brace count is 0,
// but because it is a stand alone function, the compiler
// can deliver warning information.
public void dumbMethod() {
callNotify(); // should deliver warning
public static void main(String[] args) {
Test t = new Test();
t.lockObject();
t.callNotify(); // but here, the synchronized brace count is 0, so failure!
} -
public class test {
public static void main(String[] args) {
new consumer();
new producer();
class producer extends Thread
public static int productcnt=0;
public consumer aconsumer=new consumer();
producer()
super("producer : "+ productcnt++);
start();
public void run()
try
sleep(1000);
synchronized (aconsumer)
System.out.println(this.getName()+" has prepared.");
aconsumer.notify();
catch(InterruptedException e)
throw new RuntimeException(e);
class consumer extends Thread
public static int consumercnt=0;
consumer()
super("consumer : "+ consumercnt++);
start();
public void run()
try
synchronized(this)
System.out.println(getName()+ " is waiting.");
wait();
System.out.println(getName()+ " get product.");
catch(InterruptedException e)
throw new RuntimeException(e);
}We can see the code about producers and consumers above,and the result is:
consumer : 0 is waiting.
consumer : 1 is waiting.
producer : 0 has prepared.
consumer : 1 get product.
---------------------------------------at the end of program ,consumer 0 is waiting however.
consumer 0,started in the main procedure,I can't stop it, who can tell me how tostop it with a notify.
is it real that consumer just can be notified in a procedure which claimed it?The answer is:
public class Test {
public static void main(String[] args)
consumer cs = new consumer(); // ---------
new producer(cs);
class producer extends Thread
public static int productcnt=0;
consumer cs; // ---------
public consumer aconsumer=new consumer();
producer(consumer cs)
super("producer : "+ productcnt++);
this.cs = cs; // ---------
start();
public void run()
try
sleep(1000);
System.out.println(this.getName()+" has prepared.");
synchronized (cs) // ---------
cs.notify(); // ---------
synchronized (aconsumer)
aconsumer.notify();
catch(InterruptedException e)
throw new RuntimeException(e);
class consumer extends Thread
public static int consumercnt=0;
consumer()
super("consumer : "+ consumercnt++);
start();
public void run()
try
synchronized(this)
System.out.println(getName()+ " is waiting.");
wait();
System.out.println(getName()+ " get product.");
catch(InterruptedException e)
throw new RuntimeException(e);
}Well, I simply tried to not to change your code essentially. If you gonna do something like this
but more complicated try to find other solution. -
Hello all,
I have a small problem.Before explaining the problem as such,ill give u a breif description of what i am trying to do
I have two layers.The upper layer is sender and the lower one is the reciever.Now ,there's only one reciever thread and a number of sending threads.So when one sender sends something...the reciever will start processing with the data.
In the mean time ,if another sender thread wants to send something to the reciever thread, then it must wait until the reciever enters wait state after it's current processing.
So the reciever should notify the sender thread which is in wait state...
My probelm is the sender thread if enters in to wait state once...I'm not able to notify it again when the reciever thread is ready for it.
Hope some one among u can help me out
thanking u in advance
regards
aneesyou could make the method that does the processing in the receiver, synchronized. that way, the jvm will take care of your requirement.
if you have to use the wait- notify scheme, then try using notifyAll() instead of notify() -
Confused about wait()_, notify()
hey everyone,
i have a number of executing objects running on independent threads trying to access a single method in a single object. how best can i do this. i am kinda confused. the questions i as myself are should there be a wait and notify in the method that is being called? or is the wait and notify placed in the threads that are trying to call this method.? how do i do this? also when i call notify does it only notify the threads waitin on that particular lock that the notifying thread has locked?
pleas please help me..yeah i see that that i did understand....this is what i am trying to do. i have a single method in an object which is basically a queue. i want multiple other thread to line up on this queue. so this is what i have in my code
boolean pleaseWait = false;
public synchronized void getOnLine(Truck t) {
while(pleaseWait) {
try {
wait();
catch(Exception e) {
truckLine.enQ(t);
pleaseWait = false;
notifyAll();
but this does not feel right.....i want to know should the above be done in this method or should it be done in the actual thread object that is trying to get on the line. as
public void run() {
synchronized(this) {
while(toAddress.pleaseWait) {
try {
wait();
catch(Exception e) {
toAddress.getOnLine(this);
notify(); -
Servlet, wait and an asynchronous call.
Hi Guys,
Need some guidance. Here is what I am trying to design.
I have a swt client that connects to a servlet via apache's httpclient and sends a request. Upon receiving the request, the servlet publishes it to a different component asynchronously. The component after a bit of processing (usually 1-2 seconds) will start to send responses intermittently for a given number of seconds. The servlet will receive and forward them to the client.
The challenge for me it to make the servlet wait till the component has started to publish the responses and written multiple responses back to the client.
Here is what i have come up with: The servlet gets the request from the client, calls a class that has a thread to publish it to the component. The thread will wait till the component sends back a response. Once the response is received (by a different thread), the waiting thread will be notified and the control will go back to the servlet. The servlet will flush the response and wait for the subsequent responses.
Does it sound feasible or have I neglected some key issues? Any ideas, links, code snippets would be very helpful.
Cheers,
Vic
Message was edited by:
vics_31
Message was edited by:
vics_31make your worker thread put the responces in a blocking queue and make the servlet read from the queue. So when the queue is empty it has to wait.
But normally we do not create threads in servlets its a bit unusuall design. -
Wait() and notifyall() problem in servlet.
Can anyone help me with this.....
I am creating an application which has one gateway inside which
handles for logger, dbmodule etc are made and passed to biz logic.
This biz logic using logger obj made in gateway, does the logging.
Now i hv to do serial implementation of logging i.e I have
a static member which is of type Vector, which will hold
a list of messages and associated parameters. The write() method will
create a formatted message with all values inserted, all prefixes and
suffixes added, etc. Then it will append the message to the Vector of
messages. And there will be a separate thread, which will be started
the
first time the first Logger instance is created. This thread will keep
picking up messages from this Vector in FIFO order and writing them
out.Mind you, I don't mean i need to use a single shared Logger
instance.
Separate Logger instances must be used to hold separate values for
sessionID, username, etc. Only the internal logging I/O stream handle
should be shared.
For this what i hv created logger class as follows:
logger {
SyslogAppender SA;
logger() {
new SA;
ThreadGroup TG = new ThreadGroup("string");
Logging target = new Logging();
Thread DT = new Thread(TG, target, "daemon");
DT.setDaemon(true);
DT.start();
class write {
write() {
//initialisation;
void writetovector() {
addtovector
notifyall;
class logging implements runnable {
public void run() {
while(vector is not empty){
log
synchronised(this){
wait();
Now in the servlet, in init(), logger is called with this constructor
and therefore there is only one instance of syslog appender to log in
syslog.
In service i just call the function writetovector through a method in
logger.
However when i run the implemented version of this, logging does not
take place.
I feel my implementation of wait and notifyall is not correct. Or is
there any other problem?
thanx in advanceThere are many problems with your code. It looks like you retyped it, and it now contains many syntax errors. Two problems I can see, though, are that you do not call notifyAll from synchronized code, and your call to wait is not in a loop.
Maybe you are looking for
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