How do you kill a thread?
First, you have to design the thread to allow itself to be killed. This is usually done by checking periodically as a thread goes through its task loop.
This question comes up a lot here, but here's a link to a recent discussion that includes examples.
http://forum.java.sun.com/thread.jsp?forum=31&thread=495784
Similar Messages
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I have read the many threads about killing a thread but they dont answer the question I need to know.
In class#1 I have the following snipet of code:
for (int i=0; i < docs.size(); i++)
try {
boolean blncompleted = false;
Map object = null;
OntologyCreatorThread ontThread = new OntologyCreatorThread ();
ontThread.start();
ontThread.join(15000); // Allow thread to process for up to 15 seconds.
// If thread is still running, kill the thread. I dont care about
// clean up since its only using memory and cpu, no DB is ever touched.
if (ontThread.getState().toString().equals("RUNNABLE")){
ontThread.interrupt();
ontThread.stop();
// set flag to false
blncompleted = false;
else {
// set flag to false and do a ton of other processing.
blncompleted = false;
object = ontThread.getObject();
catch (Exception Ex){
Ex.printStackTrace();
In my thread I have the following:
public class OntologyCreatorThread extends Thread {
Map object = null;
public OntologyCreatorThread(){
public void run() {
try {
// The line below takes forever to run sometimes.
object = functionCallToApi(stringOfText);
public Map getObject() {
return objects;
If the thread takes to long to run I just want to kill it.
I have tried interupt and stop and both dont work. Inside the run method of the thread I call an external API
which I pass a string of text. I can not get into that code because its from a Off the shelf product that we dont
have the code to. If the call in the run method takes to long I want to just kill this thread in the main class(#1).
No matter what I do I cant get the damn thing to stop.
The line below takes forever to run.
object = functionCallToApi(stringOfText);
Putting it in a while loop wont solve this problem because the processing is still taking place in the call to the api.
Thanks in advanceMessage was edited by:
Storm897Couple of things to consider:
1. Note that Thread.interrupted() and t.isInterrupted() are very different methods. The former clears the interrupted status so that a subsequent call will return false. The latter does not affect the interrupt status on the thread.
2. If your "atomic step one" catches an Exception, then you might be swallowing an InterruptedException. Basically the rule when a Thread is interrupted is that if it is in a blocking call, an InterruptedException is thrown. Otherwise, isInterrupted is set to true. So if you have blocking (I/O) calls in "atomic step one" and you're catching Exception, then it might be that the InterruptedException goes completely unnoticed.
3. If "atomic step one" takes a long time and you really want to abort the thread instantly, then you need some kind of method for doing so--you need to program in safe "stopping points". For example:
public class Helper implements Runnable {
private boolean _continue = true;
public void cancel() {
_continue = false;
public void run() {
_continue = true;
try {
// Do something until in safe/stable state
if(!_continue) return;
// Do something until in safe/stable state
if(!_continue) return;
while(_continue) {
// process single record in large data set
// Safe to stop at the end of each loop
if(!_continue) return;
// Do something else . . . etc.
} catch(InterruptedException ie) {
_continue = false; // Unnecessary, but here for illustration
}Casual programmers often don't care whether the thread stops safely or not, but it really is important especially if you are in the middle of some kind of transaction. That's why destroy(), cancel() et al are deprecated. -
How do you kill apps not in use?
How do i kill apps not in use?
Double-tap the home button and then swipe UP on the app preview window...not the app icon but the preview window above the icon.
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how to kill programs with IOS7 that you visit on your iphone to save the battery?
Double tap Home button, swipe the app UP to delete from multitask-list.
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How can I kill all Threads of the same class from within the run() method?
Ok
I have a class called Consumer that extends Thread
I have several Consumer threans running... but, when a certain condition is true (within the run() method) in ANY of the threads, I want to kill ALL the threads of that object.
is this possible?I know this is gonna be too demanding, but can someone please tell me why my Consumer's run() method never reaches the System.out.println( "ALL CONSUMING DONE") line
Create a multi-threaded prime number calculator that is based on the producer-consumer model
using semaphores. Your program should be able to check for prime numbers in a range specified
by the user and with a variable number of threads. Example:
$ java PrimeFind 3 5000 10000
should use 1 producer and 2 consumers (3 threads in total, obviously the minimum is 2) to find all
the prime numbers in the range [5000,10000].
The producer should: use a buffer to store candidate numbers that have to be checked for
primality.
Consumers should: read from the buffer, check if a number is prime and update the status of the
program accordingly (e.g. show the number on the screen, or save it to a file)
import java.util.concurrent.Semaphore;
import java.io.*;
public class Assign1 {
static int fromThisNumber;
static int toThisNumber;
static int numberOfThreads;
static int buffer[];
static Semaphore ready; /*This semaphore is used by the Producer to signal
an "OK" to the consumers*/
static Semaphore critical; /*This is a Mutex semaphore. It allows only 1 consumer
to enter his critical section.
static Semaphore counter; /*This semaphore acts as a counter.
Instead of having a global variable
incremented each time, we just release()
this semephore when we find a prime number
Because remember that release() increments permits
static Producer prod;
static Consumer cons[];
static int in=0;
static int out=0;
static PrintWriter outFile;
public static void main (String args[]){
try{
outFile=new PrintWriter(new FileWriter("primes.txt"));
}catch(Exception e){}
numberOfThreads=Integer.parseInt(args[0]);
fromThisNumber=Integer.parseInt(args[1]);
toThisNumber=Integer.parseInt(args[2]);
buffer=new int[Integer.parseInt(args[2])-Integer.parseInt(args[1])+1];
ready=new Semaphore(0,false); /*We initialise it to 0 because we wait
for the Producer to produce atleast a
item. Suppose ready was 1 and if
Consumer ran first he would be in an
empty buffer */
critical=new Semaphore (1,false);/*We initialise it to 1 because when
the first Consumer thread tries
to enter its critical section, it
should be allowed to;
Subsequent threads will have to
wait since only 1 thread can
access its critical section at a time*/
counter=new Semaphore(0,false); // duh!
cons=new Consumer[numberOfThreads-1]; /*numberOfThreads-1 because 1 thread
is taken by the Producer*/
//Creating Producer object
prod=new Producer();
//Creating the Consumer object and start the thread.
for(int i=0;i<cons.length;i++)
cons=new Consumer();
cons[i].start();
prod.start();
//Printing to screen and file
/* for(int i=0;i<buffer.length;i++)
if(buffer[i]!=0)
System.out.println(buffer[i]);
outFile.println(buffer[i]);
System.out.println("Total primes found between "+args[1]+" and "+toThisNumber+": "+counter.availablePermits()+"\n primes.txt written");
outFile.println("Total primes found between "+args[1]+" and "+toThisNumber+": "+counter.availablePermits());
outFile.close();*/
static class Producer extends Thread {
public void run(){try{
while(in<buffer.length) /*'in' should always be more than 'out'.Oherwise the consumer will try to access an empty index*/
{ System.out.println("producing");
buffer[in]=fromThisNumber;
in++;
fromThisNumber++;
ready.release();
catch (Exception e){e.printStackTrace();}
System.out.println("ALL PRODUCING DONE");
static class Consumer extends Thread {
int tempout=0;
public void run(){try{
System.out.println("before while"+this.getId());
while(tempout<=in)
System.out.println("before ready"+this.getId()+" "+ready.availablePermits()+" "+in);
ready.acquire();
System.out.println("before critical.acquire"+this.getId());
critical.acquire();
tempout=out;
out++;
critical.release();
if(!isPrime(buffer[tempout]))
{System.out.println(buffer[tempout]+" by "+this.getId());buffer[tempout]=0;}
else {counter.release();System.out.println("prime added: "+buffer[tempout]+" by "+this.getId());}
critical.acquire();
tempout=out;
System.out.println("tempout:"+tempout+" of "+this.getId());
critical.release();
System.out.println("ALL CONSUMING DONE"+this.getId());
catch(Exception e){e.printStackTrace();}
//Prime number-checking method
public boolean isPrime(int n){
for(int i=2;i<=(n/2);i++)
if(n%i==0)
return false;
return true;
======================
import java.util.concurrent.Semaphore;
import java.io.*;
/* 3 questions to ask Barlas
* Why error if I start the Consumer threads before Producer
* Why does the counter semaphore always give a +1 result at the end
* Is there a way I can verify that all the work is not being done by only 1 consumer thread? In other words, the workload is being shared properly
* if I put ready.acquire() outside or inside the while loop, its not making any difference, why?
* Strangely, its not making any difference if I playing with the release() and aquire() of the semaphores, WHY?!?!
public class Assign1 {
static int fromThisNumber;
static int toThisNumber;
static int numberOfThreads;
static int buffer[];
static Semaphore ready; /*This semaphore is used by the Producer to signal
an "OK" to the consumers*/
static Semaphore critical; /*This is a Mutex semaphore. It allows only 1 consumer
to enter his critical section.
static Semaphore counter; /*This semaphore acts as a counter.
Instead of having a global variable
incremented each time, we just release()
this semephore when we find a prime number
Because remember that release() increments permits
static Producer prod;
static Consumer cons[];
static int in=0;
static int out=0;
static PrintWriter outFile;
public static void main (String args[]){
try{
outFile=new PrintWriter(new FileWriter("primes.txt"));
}catch(Exception e){}
numberOfThreads=Integer.parseInt(args[0]);
fromThisNumber=Integer.parseInt(args[1]);
toThisNumber=Integer.parseInt(args[2]);
buffer=new int[Integer.parseInt(args[2])-Integer.parseInt(args[1])+1];
ready=new Semaphore(0,false); /*We initialise it to 0 because we wait
for the Producer to produce atleast a
item. Suppose ready was 1 and if
Consumer ran first he would be in an
empty buffer */
critical=new Semaphore (1,false);/*We initialise it to 1 because when
the first Consumer thread tries
to enter its critical section, it
should be allowed to;
Subsequent threads will have to
wait since only 1 thread can
access its critical section at a time*/
counter=new Semaphore(0,false); // duh!
cons=new Consumer[numberOfThreads-1]; /*numberOfThreads-1 because 1 thread
is taken by the Producer*/
//Creating Producer object
prod=new Producer();
//Creating the Consumer object and start the thread.
for(int i=0;i<cons.length;i++)
cons[i]=new Consumer();
cons[i].start();
prod.start();
//Printing to screen and file
/* for(int i=0;i<buffer.length;i++)
if(buffer[i]!=0)
System.out.println(buffer[i]);
outFile.println(buffer[i]);
System.out.println("Total primes found between "+args[1]+" and "+toThisNumber+": "+counter.availablePermits()+"\n primes.txt written");
outFile.println("Total primes found between "+args[1]+" and "+toThisNumber+": "+counter.availablePermits());
outFile.close();*/
static class Producer extends Thread {
public void run(){try{
while(in<buffer.length) /*'in' should always be more than 'out'.Oherwise the consumer will try to access an empty index*/
{ System.out.println("producing");
buffer[in]=fromThisNumber;
in++;
fromThisNumber++;
ready.release();
catch (Exception e){e.printStackTrace();}
System.out.println("ALL PRODUCING DONE");
static class Consumer extends Thread {
int tempout=0;
public void run(){try{
System.out.println("before while"+this.getId());
while(tempout<=in)
System.out.println("before ready"+this.getId()+" "+ready.availablePermits()+" "+in);
ready.acquire();
System.out.println("before critical.acquire"+this.getId());
critical.acquire();
tempout=out;
out++;
critical.release();
if(!isPrime(buffer[tempout]))
{System.out.println(buffer[tempout]+" by "+this.getId());buffer[tempout]=0;}
else {counter.release();System.out.println("prime added: "+buffer[tempout]+" by "+this.getId());}
critical.acquire();
tempout=out;
System.out.println("tempout:"+tempout+" of "+this.getId());
critical.release();
System.out.println("ALL CONSUMING DONE"+this.getId());
catch(Exception e){e.printStackTrace();}
//Prime number-checking method
public boolean isPrime(int n){
for(int i=2;i<=(n/2);i++)
if(n%i==0)
return false;
return true;
===========================
BTW, when I tried to change extends Thread to implements Runnable I got some kinda of error.
Actually, my program is pretty complete... its just that something if messed up in my Consumer's run() method's while loop... I think
I know guys its crazy to ask ya'll to look at so much code, but.... I'd really appreciate it. This assignment is killing me, been at it since 10 hours now.... -
How do you dispose a thread-handled modal dialog not thru some actions?
The code almost looks like this:
/* Thread that disposes the dialog when the time in seconds is "9" */
class AboutThread extends Thread {
private volatile Thread about;
AboutDialog ad;
AboutThread(AboutDialog ad) {
this.ad = ad;
public void stopped() {
about = null;
ad.dispose();
ad = null;
System.gc();
public synchronized void run() {
Thread thisThread = Thread.currentThread();
about = thisThread;
System.out.println("About thread is running!");
ad.start();
while (about == thisThread) {
try {
Thread.sleep(1000);
} catch (InterruptedException ex) {
System.err.println("Thread.sleep error: " + ex);
String s = new String(getCurrentDateTime("s"));
if (s.equals("9")) {
ad.setVisible(false);
ad.setModal(false);
ad.setVisible(true);
System.out.println(9);
this.stop();
/* Shows a dialog describing the User Log application */
public class AboutDialog extends Dialog implements ActionListener {
public AboutDialog(Frame parent, String title) {
super(parent, title, false);
Panel labelPanel = new Panel();
labelPanel.setLayout(new BorderLayout());
labelPanel.setBackground(Color.gray);
JLabel jlab = new JLabel("User Log 1.0");
jlab.setHorizontalAlignment(SwingConstants.CENTER);
jlab.setFont(new Font("Monospaced", Font.BOLD, 28));
JLabel jlab1 = new JLabel("Copyright(c) 2001 Soft Wares. All Rights Reserved.");
jlab1.setHorizontalAlignment(SwingConstants.CENTER);
labelPanel.add(jlab, "Center");
labelPanel.add(jlab1, "South");
add(labelPanel, "Center");
Panel buttonPanel = new Panel();
buttonPanel.setBackground(Color.gray);
Button okButton = new Button("OK");
okButton.addActionListener(this);
buttonPanel.add(okButton);
add(buttonPanel, "South");
setSize(400, 130);
setLocation(parent.getLocationOnScreen().x + 200,
parent.getLocationOnScreen().y + 200);
public void start() {
show();
public void actionPerformed(ActionEvent e) {
setVisible(false);
dispose();
at.stopped();
}ooops! i'm sorry. in the AboutDialog Class, it should be "super(parent, title, true)" for it to be modal.
anyway, it seemed that posting the partial code above of the whole app is not so understandable.
what i like to address here is that: how do i dispose or get rid of the thread-dispatched modal dialog by not making mouse clicks or any other user intervention? i wanted it to be disposed by the same thread, which dispatched it, when a certain variable value (global or local) is met. is this possible? -
How do you kill a virus/worm in MacMail?
About 4 months ago I started getting tons of weird emails a day addressed to my main Mac email address. There was a news story at the time about a virus/worm affecting PC's. I'm still getting 4 or 5 of these a day and I delete 90% of them without opening. Every so often I open one because it looks authentic. When I open it, it looks like someone's legitimate email message has been kidnapped. A nonsensical message has usually been added. It's never from someone I know. No one has complained of getting this kind of message from me, so I think a PC virus/worm that affected PC's has somehow added my Mac email address to hundreds of PC user address books. How else to explain it? This is not just spam. I've forwarded these to [email protected] without luck. I don't want to change my Mac email address because of the huge number of people that use it. But can this annoying virus/worm be stopped?
ibook Mac OS X (10.4.5)Is it addressed to your dotmac email address?
If it is your exact address with no mistakes and you keep getting this stuff I am afraid you address is out there and being passed around/sold by vermin (spammers). You have either used it to buy something from a site that may not have had very ethical morals, or you have used it in a post on a forum for all to see and this has then been harvested.
You can cancel your mac subscription and re apply and select a new address. This is a last resort scenario.
You could always sign up to one of these many sites that give you a free mail address which you can use.
Who is your ISP? They should if they are any good offer you the facility to have disposable addresses. Ask them.
Cheers
NB. Reporting these things to Spam Abuse etc will not help you one iota
because if you think about it what can they really do. It will be added to a data base and thats it. You will still get spam until you get a diffrent address or just live with it. -
When a user types in quit at my "Enter Command" prompt I wont the program to die or kill the process. Whats the command to do that?
System.exit(0);
-
How can you get a thread process id?
does anyone know?
thanks,
erikThread is an abstract idea. It's doesn't have to be implemented natively. (although it almost always is these days) So no id cept the name
-
Thread: How to tell when the thread is finished AND how to kill it?
Hi there,
I have a thread that runs in the background and does this:
class MyThread implements Runnable
public void run()
Stopper stopper = new Stopper();
//do something that takes some time
stopper.stop();
System.out.println("total time "+stopper.getTime());
}this works fine (I have a swing gui where I click a button and this thread runs and it's ok. PROBLEM IS, when I click the button again (to re-activate the thread) it seems that the stopper is not null but still counting the time (I was under the impression that ...= new Stopper() will create a new object type Stopper).
so -
1. How can I tell when thread is finished?
2. How do I kill this thread once it is finished?
the invocation:
public void actionPerformed(ActionEvent arg0)
Thread t = new Thread( new MyThread());
t.start();
}THANK YOU!You have not posted to code for Stopper, so it's impossible to reason about that
1. How can I tell when thread is finished?
Use Thread.Join() or Thread.isAlive()
2. How do I kill this thread once it is finished?
You can't and you don't. Just let the method the thread is running exit normally. Sometimes that means putting in a boolean variable to control a loop, and then exiting when the boolean is false.
Another thought - you could set the thread as a Daemon thread - when you don't have any non-daemon threads running, java will exit. -
Hi,
it say that stop() is deprecated. I also try distroy() and it is not implemeneted by design. so how do you kill a runnable??First of all a Runnable has only one method run();
So you have to call methods on the thread created with the
Runnable.
Try using the interrupt(); method
then the run loop in the run method should look
like this
public void run()
while(!interrupted())
// put code here -
Hello,
My question is simple how to kill a thread.
The background is a call to a method in a third party API, crawler4j, that locks the entire program.
The design of crawler4j is "You should stop it when you think it's enough (ctrl+c)" but as I use it only as a step in a larger program I want to stop it programmatically and not by "ctrl+c" as they have designed the API.
This is the locking callcontroller.start(MyCrawler.class, numberOfCrawlers);So I made a thread public class MyCrawlController extends Thread {
public void run(){
controller.start(MyCrawler.class, numberOfCrawlers);
}And in my main method
MyCrawlController mCC = new MyCrawlController();
mCC.start();
Thread.sleep(180000);
//Here I want to kill the mCC and all it's threadsOne problem is that my program never terminates. Probably due too the JVM not realizing that I don't want it to count mCC and it's spawned threads as alive. Any idea on how to solve this. For now I can only exit the program with System.exit(0); and I don't want that. So I need a way to stop the mCC's threads and get the JVM not to count them. Any idea on how to solve this. Even better if they can be taken by the GC.Farmor wrote:
Thanks for the answer.
I came to think about daemons and solved the problem with mCC.setDaemon(true);Really stupid that one has to do several programs and tie them together only to kill a thread.
As I only do this for other learning purposes and won't use this code or program after this week I will modify crawler4j, open source, and make myself a custom good method that will terminate itself and return to the main method properly.There are some fairly difficult problems with a number of aspects of concurrency if you forcibly stop threads, which is why Thread.stop() and related methods have long been deprecated.
It's a pity that Java can't respond to kill signals (like Ctrl-C) in a tidy way. I think they're all tied up with some of the JVMs internal processes.
In general people wind up using sockets instead of signals. -
How do you modify the default Execute thread count in Weblogic Server 9.2?
How do you modify the default Execute thread count in Weblogic Server 9.2?
How can you tune the starting number of weblogic.ExecuteThread on server startup and/or set minimum number?
Is there an option from the console?
Please let me know.
ThanksSelf tuning will automatically manage the threads but however you can still control the min and max by adding the min and max values for each instance either directly adding in config.xml or through JVM settings
1) Modifying the config.xml
Just add the following line(s) to each server definition :
<server>
<name>AdminServer</name>
<self-tuning-thread-pool-size-min>100</self-tuning-thread-pool-size-min>
<self-tuning-thread-pool-size-max>200</self-tuning-thread-pool-size-max>
</server>
2) Adding some JVM parameters
It's safer the following way :
add the following option in your command line : -Dweblogic.threadpool.MinPoolSize=100
Regards
RR -
How do you automatically expand conversations in the viewing pane to see all messages in the thread
I'm getting super annoyed since apple has started condensing the conversation in mail in the view window.
They have added the "See More from xxxxxxx" in the middle on the converations view pane.
How can you have those always automatically expand? It's a super pain, because every single
conversation I have to look at what I last wrote.
Is there are way to automate this????Thanks CT. That's not the place that I was looking at.
Organize By conversation works on the mail listing but
not in the content view window. The spot you are actually
viewing the content of the message.
Thanks for the effort. -
I DON'T WANT TO UPGRADE OR HAVE AN ADD ON EVER, DISABLING UPDATES DOES NOT WORK, HOW DO I KILL ALL MESSAGES FOR UP GRADES AND ADD ON'S FOR EVER, ONCE AND FOR ALL, COMPLETELY, THE END AND NEVER BE BOTHERED AGAIN EVER! ALSO IF I KILL MYSELF I WILL HOLD YOU PERSONALTY RESPONSIBLE.edit
There is a world of information in these forums if you use the search function near the top right of this page. Just type in NAS for example and you get many threads on the subject (marked with a green checkmark if it solved the question) another example would be Airport Exterme and sound system. Once you formulate your ideas better then specific questions can be addressed one at a time. You may find that a less expensive choice for a server might be a mac mini. Good luck with your project, ask more specific questions and update you systems profile.
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