67 Topics
 | |
 | ## Introduction ## Whenever we want to modify numbers from multiple threads running concurrently, such as modifying a counter, one of the best options is to use the AtomicX classes. The most basic numeric atomic classes are AtomicInteger and AtomicLong. In this tutorial, we will learn how to use the … |
| | ## Introduction ## This tutorial introduces the `CyclicBarrier` class and teaches you how to use it. ## Goals ## At the end of this tutorial, you would have learned: 1. How to use `CyclicBarrier` to synchronize tasks across multiple threads. ## Prerequisite Knowledge ## 1. Intermediate Java. 2. Basic knowledge … |
 | I am trying to learn Volatile keyword in Multi Threading and I came across this statement: *Volatile is preferred in cases when one thread reads and writes a shared variable and other threads just read the same. Whereas if there are more than 2 threads performing read and write both …  |
| | I am trying to understand the SynchronizedMap and I ran the below code. I get the below Output with an exception. According to my understanding the exception is caused when the get() methods are trying to access the syncmap when a thread is still executing a write on the map … |
| | I'm trying to implement Callable for Strassen's algorithm to multiply two matrices. I'm new to this, and i'm having a few issues and I can't figure it out for the life of me :( . The first problem is that the program prints out 0 for all the elements of … |
 | Hey, I have been reading Java oracle tutorials. I read this thing. Suppose, for example, class MsLunch has two instance fields, c1 and c2, that are never used together. All updates of these fields must be synchronized, but there's no reason to prevent an update of c1 from being interleaved … |
 | Hi everyone this is my first code snippet so be gentle.. I have written a basic client/server chat program that uses multithreading for listening and sending. I welcome any improvements or discussion... Thanks James |
| | i write a program its output is below G:\Java\Multithreading>java NewThread Child Thread Thread[main,5,main] Main Thread 1 Child Thread 1 Main Thread 2 Main Thread 3 Main Thread 4 Main Thread 5 Main Thread Complete Child Thread 2 Child Thread 3 Child Thread 4 Child Thread 5 Child Thread Complete in … |
| | i write a code of multithreading in which arise an race condition code is below class Race1{ public void show(String s){ try{ System.out.print("["+s); Thread.sleep(1000); }catch(InterruptedException e){ e.printStackTrace(); } System.out.println("]"); } } class Checking implements Runnable{ Race1 ob=new Race1(); String s; public Checking(String s){ this.s=s; } public void run(){ synchronized(ob){ ob.show(s); … |
| | when we create a thread like this class Run implements Runnable{ public void run(){ //You code } } class Helloworld{ public static void main(String args[]){ Thread t1=new Thread(new Run()); Thread t2=new Thread(new Run()); } } in above code thread t1 and thread t2 is creating in `main()` method its mean … |
| | Hi All, I am learning Multithreading in Java and came across this code using SwingWorker for GUI multithreading. Here is the modified code done by me. import java.awt.GridBagConstraints; import java.awt.GridBagLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.util.List; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.SwingWorker; public class MainFrame extends JFrame { … |
| | I was following along to the following tutorial - [Derek Banas Java tutorial 18 - Threads pt2](http://www.youtube.com/watch?v=G2Xd5avyk_0) and as I decided to go over his tutorial series by following along in notepad++ and compiling with the command line, so that I can experiment and test things I'm unsure about, I … |
| | I have done most of the topics in core java.But i feel for web development u have to do advanced java.Then struts then hibernate.I have heard that c# is almost same as core java(j2se)so shall i proceed with .net because i have heard its not that lengthy and u have …  |
| | I am to create a program which creates multiple threads, has them do work in parallel, and terminates when the last thread is finished, sounds simple right? Here is the curve... I am supposed to create thread objects using scanner input, and I am at a loss When I run … |
| | hi, its like this i did c++ at my school level for almost 2 years....its been 6 years since i have done any programming.....due to college studies......now i want to move to android development......for that i need to learn core java(j2se).....its been one month i have been doing j2se.....covered oops,classes,objects,inheritance,excepti... …  |
| | Hi, I have learned that servlet containers like tomcat handle concurrency in web application. I just want to get a clear comfirmation whether I dont have to multithread my business logic classes/methods(e.g database connections) when I am developing servlet applications. Cheers! |
 | Hi, I was working on an application but i'm stuck at a point now.. I'm able to send the chat messages but unable to receive any... I have two threads, 1 for sending message and another for receiving but receiving part isn't working! I think the problem is with multithreading! … |
| | I've been asked to edit the code in this post http://www.daniweb.com/software-development/java/threads/455560/java-recursion-brute-force-sim so that it "Runs the function as a thread which wouldn’t then hang the program whilst it’s waiting for the result". I've looked it up, but I'm struggling to apply it to this program, any tips? |
| | Still playing with multi-threading and Prod-Con, at this point I've been at this for days. Would love some help debugging; thanks in advance. http://pastebin.com/jhHB9kTY - Main http://pastebin.com/BZSspf3x - Consumer http://pastebin.com/ndzAADJz - Producer http://pastebin.com/p7YdzH1D - Product http://pastebin.com/rxs3WzDT - Message http://pastebin.com/JR5ywgz1 - Utiliy 2 Producers, 4 Consumers Essentially Producers push a message … |
| | I see this example frequently and thought I'd give it a shot but I've got something unexpected happening with my Queue. I have multiple threads utilizing my producer class but the output doesn't show that it is being written to by each thread. protected Queue<ProductMessage> prodQueue = new ConcurrentLinkedQueue<>(); @Override …  |
| | What is the way that need to be implemented in java to make a server broadcasts a voice to multiple clients, instead of broadcast voice only to one client? for example I am doing a server which can broadcast voice to multiple clients at the same time, now my server … |
| | public class Thread7 implements Runnable { public static void main(String r[]) { Thread t = new Thread(new Thread7()); t.start(); public void run() { System.out.println("C"); System.out.println("D"); } System.out.println("A"); try { t.join(); System.out.println("B"); } catch(Exception e){} } } Query1: On compiling this program I get "illegal start of expression" error pointing to … |
| | [CODE]/* * To change this template, choose Tools | Templates * and open the template in the editor. */ /* * MainMenu.java * * Created on Feb 22, 2012, 7:28:37 PM */ package f1carracing; import java.awt.Color; import java.awt.Graphics; import java.awt.Image; import javax.swing.Icon; import javax.swing.ImageIcon; import javax.swing.JOptionPane; /** * * @author … |
| | I'm trying to do some socket programming in java. what i have is, i've written this program to create a server and client on my local machine and make separate two threads for socket input and out put in [B]Se.java[/B] file. Similarly two separate threads for socket input and output … |
| | Hey everyone. I have recently decided to try and learn how to use java Sockets for client/server communication, as well as swing and threads, etc. and have (pretty much) completed a small client server application. The application is basically a syntax-highlighting notepad, a client swing GUI which connects to a … |
 | [CODE]class MyThread1 implements Runnable { Thread t; MyThread1() { t = new Thread(this);//create a Thread t.start();//activate the thread } public void run() //override run() of Runnable { int i; for(i =0; i< 1000; i++) System.out.print("*"); } public static void main(String args[]) { MyThread1 m1 = new MyThread1(); int i; for(i … |
| | A [B][I][U]concept[/U][/I][/B]:icon_rolleyes: has grown, may be it as wrong or right, that in Java [COLOR="Green"]if we do not take the help of [I]thread class[/I] or [I]runnable interface[/I] at all then also several threads get executed there[/COLOR]; If so how it happens with other languages where there is no concept of …  |
| | Hello Friends, I have 6 to 7 threads which are running parallely. Thing is I have to put Thread.Sleep() between each threads. How Can I optimize it? [CODE]else if (__selectedString.equals("Master DataInput")) { try { if (RecordStore.listRecordStores() != null) { System.out.println("IT FOUND RECORDSTORE ......"); RecordStore.deleteRecordStore("Company"); RecordStore.deleteRecordStore("Product"); RecordStore.deleteRecordStore("Model"); RecordStore.deleteRecordStore("Customer"); RecordStore.deleteRecordStore("Sales"); System.out.println("Delete All … |
| | I am having some problems with simulating POisson arrivals and departures in Java. I want to simulate 400 cars/hour as arrival rate and 20 cars/hour as departure rate. I have a parking capacity of 500 cars where these cars enter/exit. When I am checking occupancy values, even after a couple …  |
| | Hi, Trying to get this bit of code to work so that a train goes up the track, leaves the track and then a train comes down the track, leaves and then a train comes up the track and so on. Only one train is allowed to go onto the … |
 | Hi, I am working on a project which requires to update a JEditorPane or JTextField simultaneously by multiple clients. It is something like this. [B][1]. There are several users( i.e a group) with the same application which contains a JEditorPane. [2]. There is a group leader for a group( note: … |
| | hi guys am new to java and i have to display rotating images on a gui and use multithreading to alternate the four images. and i managed to create the gui but the images are not visible. the rotating images must be in the center of the frame. help.. |
| | Hi all, I am currently trying (and now wondering if) you can add multiple threads to a program to do the same job? Basically I am writing a web crawler for a search engine and it adds many URLs to an ArrayList which is used as a queue. I add … |
| | Hi folks, Please forgive a bit of a n00b question, but I'm working with the SwingWorker class and want to create a subclass of this which includes an input type, as well as the existing output and progress-message types (so basically I'd have "CTSwingWorker< I, O, M >"). Now, I'm … |
| | Hi all, I could really use some help with a multithreaded server/client application that I'm building. I'm first experimenting with basic concepts and then am going to implement the results within a larger application. However, I find myself stuck on a particular issue. Initially, I transfer a file from the … |
| | I'm trying to run audio in a different thread but I have no idea why but when I call wait(), my entire program seems to wait or hang.. not sure if it's deadlock since all it does is wait(), though if I set a time period, after that period it'll … |
| | Hey all. I have a deadline tomorrow, and this thing is killing me, so I come to you with hopes of help. I have a couple of classes. An info class, which converts a string to ints and puts it in the [B]values[/B] array. Another class (plotter), is supposed to … |
| | I want to make a GUI application in which I want to do something continuously (i.e. in while loop) in a different thread, until the user presses a button. In this other thread, I am accessing GUI elements and hence I have to use [B]SwingUtilities.invokeLater()[/B] for this thread. But since … |
| | [CODE] import java.awt.*; import java.awt.event.*;//for specifying windows events import javax.swing.*; import java.lang.*; public class FrontE implements ActionListener,Runnable { JTextField jav,it,c; Frame f; JButton Submit; int aa,bb,cc,tot; float avg; FrontE() { f=new Frame("Progress Calculator"); JLabel l1=new JLabel("Enter the marks here:"); f.add(l1); Panel p=new Panel(); Panel p1=new Panel(); JLabel java=new JLabel("Java"); jav=new … |
| | Hello Members, I am trying to multiply two matrices using multithreading. I get a NullPointerException on the line that is commented in Bold. Following is the entire code. Any input is much appreciated. [CODE]import java.lang.*; import java.io.*; public class Matrix_Mult extends Thread { static int a[][]; static int b[][]; static … |
| | Hey folks, recently I wrote a small application in java where it generates ip addresses in a 192.168.x.x block, and then proceeds to ping them to see if the address is available or not. The main issue with it right now is that it's extremely slow when I tested it … |
 | Hi Daniweb. I've been working on a project for quite a while, and posted many problems that I encountered on Daniweb. Thank you to all the users who helped me. Every single one of those problems where solved in less than 24 hours after posting on here. My project mostly … |
| | I need to do a pretty standard dining philosophers setup for my class. (I assume most people on here know what this problem is... if not look here: [url]http://en.wikipedia.org/wiki/Dining_philosophers_problem[/url]) We need to have a variable number of philosophers between 2 and 8, and avoid deadlock and starvation. In my design, … |
| | I've written the code already, and it compiles, but gets the following runtime exception: [COLOR="Red"]java.lang.IllegalThreadStateException at java.lang.Thread.start(Thread.java:595) at threads.ThreadStarter.run(ThreadStarter.java:52) at java.lang.Thread.run(Thread.java:619)[/COLOR] I've higlighted the line that throws the exception. I have no idea what's wrong, my knowledge in threads is sadly lacking. If anyone could help me out it would … |
| | Ok, so I wrote a very simple programme, just to practice multithreading. I know it can be coded better, but I'm still learning about this, so please be lenient. This is my code so far: [CODE]package threads; // Create a thread import java.io.File; class threads implements Runnable { // This … |
| | I am doing a project on a print spooler. I am using multithreading to support multiple clients. The problem is that I need another thread on the server side to take care of the printing by extracting jobs from a priority queue. If the queue is empty the thread must … |
| | Write a program to print * / * / * / * / * / * / * / using two child thread. One thread responsible for printing * and another for / |
| | Hello, This is my first post to the community. I have never really been one to ask of much help but I am stumped. I was asked to asked to write a word count program that received input from a scanner object. The input could consist of one or more … |
| | I am try to form a multi thread in my program but its giving this error "\Java1.java:87: cannot find symbol symbol : class mythread2 location: class Multithreading Thread mythread1; mythread2 ^ \Java.java:88: mythread1 is already defined in Multithreading(java.lang.String) mythread1 = new Thread(this); ^ \Java.java:89: cannot find symbol symbol : variable …  |
| | Hi there, All i want to do is read the jokes from a text file (using Scanner) and then write them out to three different files with three different extensions (fileName1.obj, fileName2.dat, fileName3.txt), that's part A. Part B, Create a class called FileWatcher. • This class can be given several … |
The End.