I am following this article [URL] .....
And here is my code
public class SimpleThreads {
// Display a message, preceded by
// the name of the current thread
static void threadMessage(String message) {
String threadName =
Thread.currentThread().getName();
[Code] .....
I want to know How join() and interrupt() method is working on this program?
i know how to interrupt a thread in java but somehow it is not working.
My Application looks like this
public class MyThread {
public static void main(String[] args) {
Thread testThread = new Thread(new GreatThread());
testThread.start();
[Code]....
I always read that interrupting a Thread is so much better than the .stop method but somehow the interrupt method don't work?
have written a new class that contains a thread.
From within that thread I try to call a method from within the same class the contain the thread. This method is not being called. I have confirmed that that section of code is being executed in the thread.
If you look at the following code, the thread being run is called MainThread ln 114, and the method it calls that is not being executed is called onprogressTime() ln 105;
package com.example.scott.coloursquares;
import android.content.Context;
import android.graphics.BitmapFactory;
[Code]....
I would like to avoid "Not on FX application thread" exceptions beforehand. Is there a reliable way to determine if Toolkit.checkFxUserThread is called by a specific method call? Such a check could then be included in the build process.
View Replies View RelatedI'm currently learning about Swing but I can't get my head round this piece of the code. Here is a simplified gui (not interested in the gui part but the execution)
public class SwingDemo implements ActionListener {
SwingDemo(){
JFrame jfrm = new JFrame("Simple gui pro");
//rest of code
public static void main(String[] args) {
new SwingDemo();
}
I get the above, create a new instance of SwingDemo in the main thread which starts up the gui through the constructor. However, then the tutorial says that I should avoid doing the above but do this instead:
public class SwingDemo implements ActionListener {
SwingDemo(){
JFrame jfrm = new JFrame("Simple gui pro");
//rest of code
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() { //why do this instead?
public void run(){
new SwingDemo();
}
});
}
}
Reading, it talks about an event-dispatching thread which has completely lost me... Why not just instantiate the object directly instead of creating another thread?
So I'm working on a project and noticed that my toString() method won't work. This is just an example of the type of code that I have in my real project. THIS IS MY MAIN CLASS
XML Code:
package trialanderror;
import java.util.Scanner;
public class TrialAndError {
public static void main(String[] args) {
Scanner keys = new Scanner(System.in);
String name;
String phonenumber;
[code]....
im having an issue with the 3rd thread that are supposed to merge the two sorted sub arrays , i pass the 2 subarrays to my runnable function sortlist and they are renamed IntSortList 1 and 2 and th1.start() and th1.join() are called and it works fine, but then i have another runnable constructor that takes IntSortList 1 and 2 but it does take a runnable. below is the code in my main,
Runnable InSortlist1 = new sortList(data2p1);
Runnable InSortlist1 = new sortList(data2p1);
Thread th1 = new Thread (IntSortlist1);
Thread th2 = new Thread (IntSortlist2);
try
{
th1.start();
th1.join();
[code]....
I have a paint program in Java where I can draw objects. The objects are stored in an arrayList. In the menubar the user can chooce "Back", which means the last item in the arrayList is removed. After that I want the program to loop through the arrayList and draw the remaining items.
My problem is that when I try to do that it will not work from the menu (menuItem2). If I instead add the code to one of the colorpanels (yellowPanel), from where the user can pick colors, it works fine.
menuItem2 uses ActionListener and yellowPanel uses MouseListener.
public class PaintProgram extends JFrame implements ActionListener {
public ArrayList<Draw> shapeList = new ArrayList<>();
int startX, startY, endX, endY, w, h;
private JPanel topPanel;
private JPanel bottomPanel;
private JPanel magentaPanel;
private JPanel greenPanel;
private JPanel bluePanel;
private JPanel blackPanel;
[code]....
This was shown in class the other day and I'm still not sure of how exactly it works, even after looking at it through a debugger.
public void sort(){
for (int i = 0; i < size; i++) {
Node temp1 = head;
Node temp2 = head;
Node temp3 = head;
while(temp2.next!=null){
temp3 = temp2.next;
[Code]...
Again, I didn't write this code I'm just trying to understand it. Why specifically do three different temp values need to be used instead of just one like in most sorts?
It is part of a larger program that can be found below.
import java.util.Random;
public class MyQueue implements IntegerQueue{
class Node{
Node next;
Integer data;
Node(Integer data){
this.data = data;
[Code]....
I faced with a problem, when I use method reference as a function in Collectors.groupingBy I get an error: "no suitable method found for collect". But! if I replaced method reference with a lambda expression everything works fine.
Here is the code sample:
interface Iface{
public int getPropertyOfClassA();
public void setPropertyOfClassA(int propertyOfClassA);
}
class A implements Iface{
private int propertyOfClassA;
[Code] ....
Change "C::getPropertyOfClassA" with "objC -> objC.getPropertyOfClassA()" and it works!
I am trying to remove the duplicate elements from ArrayList using .contains() if elements are primitive datatype it works but user-defined datatype does not work.
public class UserBean {
String name;
String address;
public String getName() {
return name;
[code]....
class A extends Thread
{
String str;
public void run( )
{
//random stuff
}
}
[Code]....
How to access one thread from another thread?
View Replies View RelatedDoesn't matter now, I solved it but I don't know how to delete a thread...
View Replies View RelatedI want to try and run a thread that starts running on start and quits after pressing a key.I cant seem to detect keypresses. ci cant seem to add code: Post denied. New posts are limited by number of URLs it may contain and checked if it doesn't contain forbidden words.
its just a code snippit without links or anything..this is a small part... but how do i add a keyListener in here that listends to a random key?The class implements KeyListener and the overrided method "keyPressed" sets the isRunning boolean to false... but the keyPressed method is never executed.
public static void main(String[] args) {
Thread thread = new Thread() {
public void run() {
while(isRunning){
System.out.println("running");
try {
sleep(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
};
thread.start();
}
how to start a new thread
public class pracDraw extends JFrame {
private Color red=Color.red;
public int i;
private Color white = Color.white;
JPanel pr=new JPanel();
JTextField t=new JTextField();
[code]....
If u run it you can see that the JTextField (t1) is drawn on the panel along the line but it does so with a gray border. How do i eliminate that grey border and only draw the text field along the line and finally make the text field green after it reaches the end of line?
import java.awt.Graphics;
import javax.swing.JFrame;
class node{
node(int a,node next){
this.a=a;this.next=next;
[Code] ....
The code was ran not right, I want it's result is: 1 2 3 4 5 and delay(1000) every time that it prints a number
Example: 1 (delay(1000)) 2 (delay(1000)) ....
And the paint must do that
I have a program ive been working on and it works, but the flags in the runnables seem to shift the output down 1. for instance i commented playa3. start(); to see whats going on, if i just run playa1 i got no issues, as soon as i enable playa2, i get this output:
Game continues...
Dealer places King and Queen on the table.
Game continues...
Dealer places Queen and Ace on the table.
Player one with 'Ace' places his card on the table.
Player one with 'Ace' wins the current deal.
King Queen
Game continues...
Dealer places Queen and King on the table.
Player two with 'King' places his card on the table.
Player two with 'King' wins the current deal.
Queen Ace
the second time the dealer deals, player one places his cards on the table when he was supposed to do that for the first deal which he didnt. the last line there, (king queen) is just a print statement that is referring to the dealers hand that, that iteration is responding too. below is my code, i
import java.util.*;
import java.io.*;
import java.lang.*;
public class P5
{
public static int i, count, dealerFirstCard, dealerSecondCard, player1, player2, player3;
public static String cardSet [] = {"Ace","King", "Queen"};
public static volatile boolean dealerFinished= false;
public static volatile boolean playersFinished= false;
[code]....
I start my thread, it's for a real basic game I'm learning. Everything was working fine, until I got to recognizing keys. It runs, and I can close using the mouse on the close command, but the keys aren't being generated from the keyboard. I copied it to a working sample, and here are the two files.
package testkeys;
import java.awt.Canvas;
import java.awt.Dimension;
import java.awt.image.BufferedImage;
import java.awt.image.DataBufferInt;
import javax.swing.JFrame;
[Code] ....
The idea was to set the return value to true if any key is pressed, thus quitting, for this short sample program. Problem, it never recognizes any keys pressed on the keyboard. New to java and threading.
I am new to java and still learning. I am trying to execute the code below which compiles successfully, but getting the following error:"Exception in thread "main" java.lang.NoSuchMethodError: main"
Code:
class Dog{
int size;
String name;
String breed;
void bark(){
System.out.println("woof woof");
}
}
class DogTestDrive{
[code]....
I have objects (baddies in a game) that have individual clocks/counters assigned to them (when I make an object, I fill an integer based array list with a new digit entry at a value of one) that all happens in threads. then in another thread, I am checking the whole list of clocks, to see if any are equal to a wanted value , then I am taking an action and reseting the clock at that point on the array list.
now, the problem is:even though my code says " yes, I've taken that action because the value of array position x was >= specified value and I will now reset the clock" it doesn't reset the clock. Here is what it looks like
*these are excerpts taken from a really big program, however they should stand on their own as they are individual classes
Java Code:
public class levelclock extends Thread {
public void run() {
while (Run2 == true) {
if (Run == false) {
try {
Thread.sleep(100);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
[code]....
(Attached, just open up the zip and read the .txt)
I created a main class called X and two Y and Z classes.
Y and Z implements Runnable classes.
class X contains a static array A that can be accessed in Y and Z.
The Run () method of the class Y reads an input file and populates the vector A.
The Run () method of the Z class uses data stored into the vector A to process some data.
The objective of using threads in this problem is: as the vector A is filled in the Run () method of class Y, the Run () method of the class Z will processing the received values in the vector A.
to do this I did the following calls in the main method of class X:
ObjectY y = new Y ();
Thready thread = new Thread (objectY);
threadY.start ();
ObjectZ new Z = Z ();
Threadz thread = new Thread (objectZ);
threadZ.start ();
is that correct? I'm getting the expected results, but dont know if the code is parallelized in fact.
I need a small example of an object which is visible to two different threads.
Does saying "an object is visible to two threads" mean that it's fields or methods are being used in both the threads? I am not clear about that.
I have situation where a user can request java server to send a value to an embedded device, and if the device is asleep, that value needs to be stored in a queue until the device wakes up and sends a position to java server, at which point the server checks if there is a value in the queue and if there is, it then sends that value to the device. The maximum size of the queue is 1 for now. And if the user makes continuous requests to java server, the old value is removed and the new value is added.
Initially I was looking into BlockingQueue, but the problem with that is, well, it blocks. queue.put(value) will block if queue is full, and queue.take() will block if queue is empty. I can't have something that blocks. When the device responds to server, server checks if value is in queue, if it is not then the server carries on the rest of its responsibility. Thus, I then entertained ConcurrentLinkedQueue. While queue.offer(value) and queue.poll(); allow you to add and remove values respectively from the queue without blocking, it does not allow you to set a maximum size limit of the queue. My queue must have a maximum size limit and it has to always be the newest value the user submits to the queue (where old values are removed).So this is what I came up with:
Java Code: class Unit {
private List<Integer> cmdQueue;
public Unit(){
cmdQueue = Collections.synchronizedList(new LinkedList<Integer>());
[code]....
I use Collections.synchronizedList, as I do here, do I still need to use synchronize as I did above?
I have two classes, where main class is simple with only main function in it. Another class extends Thread and there's couple of functions I want to execute from main class.
Problem: I try to get other.shut() to be run in main class catch() block, after I have stopped the other class's running thread (e.g. by ctrl+c).
I think I need to somehow "pass" the exception from other class to main class so it goes to the catch block?
Code for main class:
Java Code:
public class MainClass {
public static void main(String[] arguments) {
OtherClass other = new OtherClass();
try {
other.exec();
} catch (Exception e) {
other.shut();
[Code] .....
Here I want to make a simple program where a Ball keep bouncing forever, then I add a MouseClick Listener to stop and resume thread (I mean, to stop moving Ball and to resume again). The problem is I can stop the thread using wait(), But I can not resume it. Below is the code
public class TestResumePauseBall {
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public synchronized void run() {
Field aField = new Field();
[code]....
At first I think that notify() must be called from another active thread. So I add a 'class Timing implements Runnable'. Then I call notifyAll() from class Timing. But still it was failed.
After wait() called on Ball's thread, the whole frame also freeze. I can not understand why this happen?
If this test success, I will add 1 one more ball and add keyboard keys as controller of ball's movement.