I am writing a fairly complex Java server application which has a significant background processing portion in addition to the usual request-response processing. Some of the background processing is done in ... |
hi to all i have created a server class with threadpool as shown below and it makes use of workerRunnable class . the problem i am facing with this code is ... |
can i have code of serverprogram which accepts several client connections using THREADPOOL concept,where each client send a file to server and server should respond to them with respective response file......i ... |
I want to learn to write a thread pool in Java
Can anyone point me to useful resources ?
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I am looking at the advantages of threadpooling design pattern in Embedded systems.
I have listed few advantages, please go through them, comment and please suggest any other possible advantages that ... |
I am trying to proccess a queue of tasks from a database table as fast as possible while also limiting the number of threads to process the tasks.
I am using a ... |
I need to make a program with a limited amount of threads (currently using newFixedThreadPool) but I have the problem that all threads get created from start, filling up memory at ... |
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Please explain Thread Pool and what is the use of Thread pool,please give me a real time example?
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I have a fixed thread pool that I submit tasks to (limited to 5 threads). How can I find out which one of those 5 threads executes my task (something like ... |
I may imagine some tasks scheduled to take a very long time and ScheduledThreadPoolExecutor would create additional threads for the other tasks that need to be run, until a maximum number ... |
Is it safe to start a thread pool in an objects constructor? I know that you shouldn't start a thread from a constructor, something about the "this" pointer escaping (I don't ... |
I have a ScheduledThreadPoolExecutor that seems to be eating Exceptions. I want my executor service to notify me if a submitted Runnable throws an exception.
For example, I'd like the code ... |
I use ThreadPoolExecutor to run some actions, at some time I cancelled some future tasks and stored it into a list to arrange some other tasks to do, and after that ... |
I was trying to do a Threadpool program in which i need to create a fixed no,of threads and allocate each thread to each process.Each of my process are written as ... |
First and once more, thanks to all that already answered my question. I am not a very experienced programmer and it is my first experience with multithreading.
I got an example that ... |
how do I set time limits for individual threads in a thread pool..?
The parent thread need not wait until every thread finishes and returns back. Instead it should fetch the ... |
I have a scenario where I use threads.
Firstly I have a folder where there are files which get updated frequently.
So, I wrote a thread which reads the contents of the folder ... |
I have mainly CPU intensive operation which is running on a thread pool.
Operation however has certain amount of waiting foe external events which doesn't happen uniformly in time.
Since in Java, ... |
Using Executors.newFixedThreadPool(int nThreads) is a nice way to minimize the overhead of creating too many threads, but it may lead to a deadlock in case that all threads are waiting for ... |
I want "runnable" to run at 5tps. This is not executing paralelly.
package tt;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.FileWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import java.util.logging.Level;
import java.util.logging.Logger;
public class mySpawner {
public ...
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I have a Java application that uses the Executor framework and I have code that looks like this
protected ScheduledExecutorService scheduledExecutorService = new ScheduledThreadPoolExecutor(5)
My understanding is that internally the JVM would create ... |
There are Jobs.
Job contain Different Tasks
Job1
- Task 11
- Task 12
- Task 13
Job2
... |
When using a thread pool, is it beneficial to still use singular thread objects for a specific task. I'm wondering in terms of a server in Java, whether or not the ... |
I am currently implementing a program that requires me to handle threads and process.
IDEA:
- There are multiple java processes running and each process may have multiple threads.
Current java implementation is ...
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I am looking to implement a Java application that will compute a set of tasks to execute. The tasks will have dependencies on each other, forming a directed graph. ... |
I'm planning to use Netty to design a TCP Server. When the client connects, I have to immediately start pumping
XML data to the client continuously...for hours/days. Its that ... |
i'm triyng to experiment the multithread programming (new for me) and i have some questions.
I'm using a ThreadPoolTaskExecutorwith a TestTask which implements Runnable and a run method wich sleeps for X ... |
I am currently thinking about how to design a multithreading system in Java that needs to do some heavy network processing and database storage. The program will launch three basic threads ... |
I have a problem which I don't really think has a solution but I'll try here anyway. My application uses a thread pool and some of the threads in this pool ... |
I had a quiz for Threads last week and I got these 2 questions wrong. I was wondering if anyone can help me get the right answer for these. Thanks.
Are there ... |
Currently i am in a process of developing a application which can work in a multi threaded mode. As part of testing on my local machine (Intel Core I5) i tested ... |
I am trying to build a server that can concurrently accept files from multiple clients.
But it is submitting files sequentially and I don't understand why....
Can anyone help? Thank you
I post my ... |
I have a command line application. It runs a loop say 100 times and in the loop schedules a task using a thread. I am using ExecutorService so there are 4 ... |
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Dear sheriff, I apologize, however I was unaware of this policy. I remember seeing a notice that I must agree to the rules, but to be honest I just assumed the rules were no profanity, being mean etcetra. The naming convention for the user handles is not very common, perhaps if this were advertised more clearly when a user is registering ... |
I tried to code in the java code listed at this site... http://www.sys-con.com/java/source/3-2/34.htm I wrote my own ClientHandler... Basically, it's just a knockknockjoke server. Anyway, I'm having problems getting it to work correctly and am unsure of why or how to debug it. One client can connect okay, but when I try a second one it hangs waiting to enter the ... |
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[which means if request is greater than the pool size ,it has to be wait in queue,and released when any request in-line is served] The problem with thread object is ,it can be called start() only once,if you try to call again ,it will through illegal state exception.So it is not possible to put all the thread object into stack and ... |
I have implemented thread pool twice in two project. Do U mean U want to have coding sample? My implementation is that once the pool is instantiated, it will itself create a cluster of threads which are available for assigning. Threads will be assigned to the requesters in an ordered manner which can be replaced with any mechanism, some may like ... |
Is the following implementation of pooling correct. I see that when i run out of the threads in the pool and i am creating new threads to handle the requests, but it does not seem to happen. Something seems to be wrong there. Can any one help me out. Thanks in advance. Bye ================================= public class Main { public static void ... |
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Hi, there, I've got "java.lang.IllegalStateException: Unable to access thread pool due to java.lang.NullPointerException" error info when use org.apache.avalon.excalibur.thread.impl package to manage thread pool. public static void main(String[] args) { try { DefaultThreadPool dtp = new DefaultThreadPool("ThreadPoolTest", 1000); Thread t = null; while (true) { try { // t = new Thread(new MyRunner()); // t.start(); ThreadControl tc = dtp.execute(new MyRunner()); Thread.sleep(1); } ... |
Thanks for ur code. Im getting the result but Im little bit confused how again first thread A is starting after completion of J thread. Here there is some more task for me if the number of threads are dynamically increasing and I need to perform a task at 12:00am then the same task shud again be performed at 1:00 am,u ... |
I had posted a similar question a few weeks back, but this is a bit different... My idea is to receive datagrams continously frm udp port, process and write them to a file. I have a class UdpReader (extends Thread) to read them. I downloaded a ThreadPool class (that implements a thread pool). This thread pool has a runTask method, that'll ... |
I have a server which is thread-safe, can server multiple clients concurrently. I had no problems when I had 5 -20 clients running concurrently and when the thread-pool size was set it 5. But, when I increase the thread-pool size to 20 and when I try to run 20 clients..I am getting the SQL exception ..."MAXMIMUM NUMBER OF PROCESSES EXCEEDED(200)". It ... |
I built a Connection pool that schedules threads to receive connections as they open up. Currently I am saving the thread name, but I know this is not guaranteed to be unique and may be diff. across OS's as well. However, the only thing I can think to do is save the Thread ref itself. Is there anything wrong/bad about this? ... |
OK, so I have a simple system. I have a "LogManager" and "Loggers" loggers are things that write to file/console/DB, whereas Log Managers hold loggers and dispatch messages between them... Log managers could be threaded, timed, etc... So I am working on a threaded log manager. So far I've been working my ass of without any result or any useful help... ... |
Hello all: I need to develop an application in java that will be responsible for receiving simultaneously numerous jabber messages from different sources. Based on the contents and the types of the jabber messages, different methods might need to be executed. What I would like to see happen is to have a thread pool containing a predefined number of threads and ... |
Has anyone used the Jakarta Commons thread pool? I took a quick look through the code and found it surprisingly simple. On a recent thread I suggested a queue-driven idea instead of a thread pool ... it turns out the commons thread pool is implemented exactly as such a queue. So it made me feel kinda smart for a few seconds. ... |
Hello Everybody, I have a Java Program that reads an XML document ,parses it and loads the file into a database(table).This process is for every single XML File and there are 100's of files.So its takes a very long time to load all these documents.I need to multithread this process so that the XML's can be loaded simultaneously.I am kinda confused ... |
You can find a thread pool in Doug Lea's util.concurrent packages. There's also one in the Jakarta Commons sandbox. There are plenty more scattered in random places and random projects of all kinds. The idea is that creating a thread isn't just a matter of allocating a few bytes of memory. Threads need their own stacks, among other things, and may ... |
hello, Could you help me find out an implementation of Thread Pool,that keeps track of minimum no. of threads,max. no. of threads in the pool,the increment size of threads,number of idle threads,idle time allowable for a thread,etc... I also need to know if it is possible to have >5000 threads in a ThreadPool,beacuse I get OutofMemoryError,when I used a ThreadPool( which ... |
Hi, I would like to use a thread pool to do a job requiring several asynchronous tasks. I looked up some TP implementations available including the one in Java 1.5.0. When I assign a Runnable task to a thread in the TP what happens to this thread when the task is finished. Is this thread returned back to the TP or ... |
hello recently,i am studying the Doung lea's thread pool.and plan introduce it to my projects,i write following code to test the "PooledExecutor": public class MyTestClient { public static void main(String args[]){ PooledExecutor executor=new PooledExecutor(new BoundedBuffer(10),5); executor.setMinimumPoolSize(2); executor.setKeepAliveTime(-1); try{ for(int i=0;i<40;i++){ executor.execute(new WorkerThread()); } }catch(Exception e){ e.printStackTrace(); } } } class WorkerThread extends Thread{ public void run(){ try{ Thread.sleep(5000); System.out.print(this.getName()+" is running!!\r\n"); ... |
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hello experts, I have a quetion on the threads. I have designed a thread pool. the thread pool has a behaviour shrink and re-size based on load. And also i have implemented a listener which gets events for pool resize , pool initiate, task started, task completed etc.., Also I have monitor that i have implemented which is monitoring the pool ... |
Sandbox projects are mainly project proposals that haven't yet produced a workable release. That's why you find nothing there yet except project documents, it's still in its infancy. Your best bet is probably to roll your own. I've found the Jakarta commons less than nice to use and most OS projects outside the Apache/Jakarta scope of low quality and/or dead. |
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JDK 5 has a nice one; start with Executors and BlockingQueue in the doc. For older JDK's look for Doug Lea's concurrency package, which was the foundation for the one in the Java 5, or a beautifully simple one in the Apache Commons. Here's how easy the Java 5 stuff is to use: private void acceptClientRequests() { executor = Executors.newCachedThreadPool( this ... |
Hi All, Could u pls suggest the best idea for the below requirement. i do have "ArrayList" which all fully qualified releative path of all files in server. my main programs reads from "harddisk" based on the "config.xml" which has extensionto scan (like doc or jpg ...) so it will store in "ArrayList which satisfies all config file properties. I need ... |
First, I will admit up front that this is a homework assignment. I need some guideance, but I am not looking for a final solution. However, I have no other resource at this time to eyeball this with me to see what is missing, so any good nudge will be greatly appreciated. I have a class DateServer that is supposed to ... |
Apache Commons has a thread pool, too. I found it educational to read and pretty easy to see how it works. One part of it is a blocking queue. You don't have to roll your own any more with modern JVMs but if you're on 1.3 or older these are pretty cool little classes. |
Hi Ranchers, im working on a thread pool(TP) implementation, but im having problems finding a way to kill (i.e. remove) an inactive thread (i.e. worker). When my TP is started I initialize a number of workers. After a period of time (or when something happends) I'd like to be able remove 1 inactive thread. Im not quite sure what to put ... |
What JDK version are you on? I guess you're not able to use the thread pools in 1.5. I often recommend the commons thread pool but moved to 1.5 before I ever really used it. If it exposes the configuration APIs you need it should be easy to build a JMX bean to call those APIs. What do you want to ... |
All right, it looks like the latest Sun tutorial doesn't provide any example code using Executors. Still, I think that JDK 5's new classes will ultimately be simpler to use than the old classes. Here is an article with more detailed examples of how to use executors. And here is another. [Meir Yan]: why do i need the Thread.sleep In that ... |
hi all, please tell me how i should implement thread pooling using jdk1.5 . by using java.util.concurrent.* package. what i have to do. i have to make a class and i have to put for loop that send continuously message . thread pool of size 100 threads. when more then 100 message are coming then there should be queue for message. ... |
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I know that this has been discussed quite some time in one form or the other but on searching the forums i could not find an appropriate answer. Consider the following scenario: I have a framework where i allow people to drop code(implementing an interface) that can be executed at various places in my application flow. The code is given appropriate ... |
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Hey yo, I have been doing some java work with threads as of late and one thing that has constantly been popping up is thread pools. Now whilst I understand the idea and concept I have been having trouble locating a straight forward simple and most of all COMPLETE example or tutorial somewhere on the Internet. Everyone seems to have this ... |
Hello, I want to write Thread Poolusing Java for some repititve task which is controlled through Job Scheduler.Job Scheduler will run after interval of 2 minutes.Can you please provide me few guidelines regarding how to write thread pool in Java. My application will be deployed on Application Server and I am using JDK 1.4. I know there is a java.util.concurrent.Executors class ... |
Following question was asked to me in one F2F interview : We are using one third party library and there is one call e.g. doUpdate() which performs operations like open connection, network calls, close connection. This method has one constraint. If connection goes above 20 then it will throw an error of MAX_CONN_EXCEED. As this is third party library, we can ... |
Hi I found my self understanding what is asynchronous thread rather than doing what I really want. I always thought that if you have a synchronous thread that will run and stop according to (say events), then it will be a good idea to not recreate that thread again. just ask a thread pool to reinitialize that created thread and re-Start ... |
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Hello, I have this common situation in which I have a set of tasks to execute. Each tasks has: - a part that execute a certain code (it spends time Te) - and a part it has to wait for an amount of time that I call Tw. In this situation it's good using a ThreadPool of size (1+ Tw/Te). The ... |
Hi All, The requirement is to process many request simultaneously without blocking the request more than a second. else the client will be timed out before receiving the response. Also the normal thread pool size should be configurable and that will be alive in all time. For e.g: Configured 50 as thread pool size. Initially there should not be any thread ... |
I'm trying to set up thread pooling so that I can have many threads consuming and processing messages from a JMS queue. I thought I had found the solution upon reading about ThreadPoolTaskExecutor however I can't seem to find a way of prioritising thread execution. If I can briefly explain an abstraction of what I'm trying to do: 1. The jms ... |
That sure sounds like a homework assignment. Presumably your instructor wants you to think about the fact that network delays in doing a single ping will cause very low load on the cpu so multiple Threads could be working "at the same time." So what have you learned about use of Thread Pools to manage multiple Threads so far? Bill |
Hey guys...i have implemented threadpool concept (below) using Exceutor class..can you please let me know whether the steps that i have done is rite??? import java.util.ArrayList; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import java.util.concurrent.Future; public class ThreadPoolTest2 { public static void main(String[] args) { // int numWorkers = 5; //Integer.parseInt(args[0]); int threadPoolSize =2; // setting the number of threads String sMessage = null; ... |
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Hi Friends, I want to find the elapsed time for my multithreaded program.I have used ThreadPoolExecutor to manage threads.When I am not using the Thread pools,I used to use join() in the main method,so that my main thread will not terminate before the child threads terminate and hence I am able to find elapsed time.But when I use Thread pool ,even ... |
Hi friends, I am calculating the 7th fibonacci number using threadpool. I am recursively creating threads to calculate. I am not able to figure out how to make the parent thread of each recursive call wait for their child threads to complete. Since I need the previous result of any computation for the next set of result,I am not sure how ... |
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First let us understand what is Thread pool Thread pool is concept where in a pre-defined number of threads can be created/initialized in advance (for example, during server start up) and stored in virtual memory. Threads are created in advance because this reduces the amount of resources required to create new threads at run time. So, Thread pool eliminate the need ... |
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hello, i have a program that download's a webpage to a string, and makes some process to it. now i need to make a thread pool with 4 threads, that take all the hyperlinks from the original page, and does the same process, with 4 threads only. i'm really new to java, so i would appreciate detailed explanation. i've read few ... |
want to create my own ThreadPool executor class So, go ahead and create it. I find a couple of things a bit obscure. First you say you want "some simple example with code". But you have the code! In this thread and in the last you were pointed to java.util.concurrent. Of course you may feel that that code is not particularly ... |
Define 'tuning'....if there are many requests, you should have a queue to handle those requests in turn. If there is a lack of requests, your should have threads waiting for requests. If by tune you mean make more efficient, there should be a clear demonstration that your present code will present a problem in a particular scenario to make the refactoring ... |
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Hi, I am using Thread pool in my application . where i am creating threads (and assigning name ChildThread1,ChildThread2 ..) and put them in the Thread pool using the execute() method. In my application i try to get the name of the current active threads. So i use Thread[] threadArray = new Thread[Thread.activeCount()]; int numThreads = Thread.enumerate(threadArray); for (int i ... |
Dear friends, I am writing a client-server program in which the client and server communicate using SUN-RPC. The client reads a file containing some numbers and then spawns threads which it uses to request the server for a service. These threads are executed using a thread pool. Till this time, it's working fine. But when it comes to the server, the ... |
Boolean value indicates - true if this semaphore will guarantee first-in first-out granting of permits under contention, else false. /** * This method ensures that before obtaining an item each thread must * acquire a permit from the semaphore, guaranteeing that an item is * available for use. * * * @throws InterruptedException */ public static void waitForRunQuota() throws InterruptedException { ... |
98. ThreadPool forums.oracle.com |
A servlet engine creates a separate thread for every request, assigns that thread to the service() method, and removes that thread after service() executes. By default, the servlet engine may create a new thread for every request. This default behavior reduces performance because creating and removing threads is expensive. Performance can be improved by using the thread pool. |
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