I am trying to program an A* algorithm and I cannot even get past the buttons. I need a 2D array of buttons to handle this problem but I am getting the following errors.
at java.awt.AWTEventMulticaster.componentShown(AWTEventMulticaster.java:162)
at java.awt.AWTEventMulticaster.componentShown(AWTEventMulticaster.java:162)
at java.awt.AWTEventMulticaster.componentShown(AWTEventMulticaster.java:162)
at java.awt.AWTEventMulticaster.componentShown(AWTEventMulticaster.java:162)
import java.awt.Color; import java.awt.GridLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.*; public class Screen implements ActionListener { public JButton[][] b=new JButton[200][200];
[Code] ....
I am trying to create the A* Algorithm and I REALLY need a 2D array to handle this.
This is the error:
Java Code:
at java.awt.AWTEventMulticaster.componentShown(AWTEventMulticaster.java:162) at java.awt.AWTEventMulticaster.componentShown(AWTEventMulticaster.java:162) at java.awt.AWTEventMulticaster.componentShown(AWTEventMulticaster.java:162) at java.awt.AWTEventMulticaster.componentShown(AWTEventMulticaster.java:162) at java.awt.AWTEventMulticaster.componentShown(AWTEventMulticaster.java:162) mh_sh_highlight_all('java');
Whilst pre-preparing for java certification, one of the online mock exams has slightly confused me by saying my answer was incorrect for multi-dimension array 'declaration and instantiation'.
This is one of the answers i chose - which was marked as incorrect
a) int[][] array2d = {{123}, {4,5}};
Which looks absolutely fine to me.One of the other answers, which i agree is correct and so does the mock exam is
I'm finishing up this assignment, and I'm stuck. These are the last 2 instructions:
. Roll each of the Dice by invoking the roll method on each Dice in the array. . Keep track of the totals sum of all the dice in the array. Be sure to roll the dice array at least 10000 times.
How to finish it up?
Here's my code so far:
package homework3;
import java.util.Random; public class Dice { private int numberShowing; private final int numberOfSides; private static final Random randomNumber = new Random(); public Dice() { numberOfSides = 6;
how to implement action listeners for an array of buttons. The program has an array of buttons like the number pad on a keyboard, when the user clicks a button the number/button clicked will append to the textfield. So far I'm just working on the GUI.
I have made a server/multi Clients where Clients send Double data but my problem is that the clients send this data to Server only wonce, and the server waits again the connection from client. (I have to run the clients manually each time)what i'm looking: the client should always send data to server. like an infinite loop.
I have been practicing writing java code, my university course is going to cover socket programming and multi-threading.
I am presently just starting to write myself a framework for all multiplayer games I may make in the future, my aim really is simply to practice and understand better and this time, im not using an ide, just sublime text, all new grounds for me, I have a good basic understanding of the subject but I want to be fluent.
import java.net.*; import java.util.ArrayList; import java.io.*; /*SMOOTH THREAD SAFE MULTI CLIENT HANDLING CLASS. * *This class will create connection objects when a connection is detected, these connections will run in a separate thread and update an array list in their parent class containing their last sent data
I have a problem with multi threading calling with for loop. I have those two and many other classes in one jar file but n 2 different packages.
When i execute the jar file first runs the Aclass, from where i try to run multi threads. From the run() of the class RunTheGame i call many other classes which are in the same package. Like you can see from the for loop is executed the threads.
The problem is that when the second thread starts the first one is stopped this happens for all the threads, more simply when a new thread starts the old one is dead.
It seems that liken the threads uses the classes called from run() of the class RunTheGame as non multi threaded. It gives this error:
Java Code:
Exception in thread "Thread-0" java.lang.NullPointerException at thePackage2.EClass.getWhiteRemaining(EClass.java:49) at thePackage2.EClass.isFinal(DClass.java:84) at thePackage2.Spiel.<init>(Cclass.java:76) at thePackage2.RunTheGame.run(RunTheGame.java:198) at java.lang.Thread.run(Thread.java:745) mh_sh_highlight_all('java');
All the above refereed classes are called from the from run() of the class RunTheGame . Like i understand all the threads use those classes as non thread autonomous classes.
Java Code:
public class Aclass { private static Thread t[]; public static void main(String[] args) throws IOException { for (int Game = 0; Game< 10; Game++) { t[Game] = new Thread(new thePackage2.RunTheGame(aplayer, bplayer, Name, ID , Pmach)); t[Game].start();
My task is to create multiuser console chat program. During whole day of poking around , i finally stand on such concept:
1. When running , Server part must stay into while(true) loop and create threads on each ServerSocket.accept() call, providing socket object inside thread. i.e.
while (true){ System.out.println("Waiting for client to connect"); Thread t = new Thread(new Runner(servSocket.accept(),listOfClientSockets)); System.out.println("Starting thread"); t.start(); }
2. Client side always stays within while(true) loop and waiting for user input with ScannerInstance.nextLine() method. As soon as user prints something and hits enter, data being captured from scanner and thrown to socket output stream to the server.
My question is : if all parties (X clients and server) are actually in waiting mode (server is waiting for connections and each client is waiting for user input), who will refresh the screen for each client to draw the messages other parties sent?
At this time , each party see updates only when he hits enter and while loop does next iteration reading data from buffer and displaying on console.
Just some questions regarding a Consumer producer program I am not understanding. Here are the two classes Below and my questions are :
1. In the main method for NamedConsumer, we created an instance of the class and call it "consumer" and we start it. Then we create another instance and we give its reference to the same variable. Doesn't this in turn destroy the original reference of the first instance we created which was started? Could we have done
NamedConsumer consumer1 = new NamedConsumer( "One", producer ); new Thread( consumer1 ).start(); NamedConsumer consumer2 = new NamedConsumer( "Two", producer ); new Thread( consumer2 ).start();
2. we called start on two difference instances of the NameConsumer class. Doesn't the "run" method need to be synchronized since two threads are hitting it?
Producer.Java
Java Code: public class Producer implements Runnable { static final int MAXQUEUE = 5; private List<String> messages = new ArrayList<String>();
public void run() { while ( true ) { putMessage(); try { Thread.sleep( 1000 );
I have been trying for days and nights , no compile error , but alot of NPEs error .......
This is my Test program
import java.util.*; public class Test { public static void main (String[]args) { int totalShares = 0 ; double totalCost = 0.0; double totalProfitLoss = 0.0;
[Code] ....
I am expecting a output like this (Which I have error running:
Tracking of Stock : FCS 8 shares has been brought at $37.61 Total shares now 8 at total cost $300.88 33 shares has been brought at $36.31 Total shares now 41 at total cost $1499.11 17 shares has been sold at $42.67 Total shares now 24 at total cost $773.72 19 shares has been sold at $32.31 Total shares now 5 at total cost $159.83 31 shares has been brought at $33.85 Total shares now 36 at total cost $1209.18 28 shares has been brought at $36.37 Total shares now 64 at total cost $2227.54 20 shares has been brought at $35.49 Total shares now 84 at total cost $2937.34 At $36.00 per share, profit is $86.66
I would like to create list of entities which is populated by a search function with the data coming from our REST webservice. However I would like it to be multi-line, with the first line being details from the entity itself and the second line buttons for options that can be performed.
So as an example say my entity is People, the first line would contain columns for first name, last name, gender, DOB, etc. The second line would be buttons for "Edit Person", "Print Person details". With the standard TableView I can't see anyway to alternate between one row of data and another row of buttons.
So I am trying to create a Multi-Player game in java, and I have a Game server and a Client. They normally connect with either but I would like to add a login server so that there can be an option to go to a different world then just the main one. It will have the same map and data but will be separate from the Players that are on world one per say. Now if you are on world two I would like it to have the option for you to be able to Private message players that are on World one. That is where the login server comes in to play.
I am still new at Java and would like to be able to understand Packets and how to handle them more clearly. So far I have gotten the basis of the login server connected to the server and the client connects to the server via the login server. But I am getting a bunch of "unhandled packets" and I would like to know how to handle them. Here are some bits of the code.
I created a simple Hangman game. It functions correctly, the only issue is when the file contains a phrase (2 or more words), spaces are not displayed when the program is run. For example, if the phrase was Java Programming Forums.
It would appear as _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.
I want there to be spaces in between the words. How could I fix this? What would I need to add to my code?
import java.util.Scanner; import java.io.*; public class hangman{ public static void main (String[] args) throws FileNotFoundException{ Scanner kb = new Scanner(System.in); String guess; String guesses = ""; int wrongGuess = 8;
Firstly, my code is just a demo of my multiplayer game (2 or more players can play simultaneously) to demonstrate my problem without any extra things. I have successfully implemented peer-to-peer (P2P) communication in my game. Later, I decided to add support for client-server communication (ie a central server which is also a player) in my game. It should be much easier than P2P. Now here is the problem:
Suppose, I have 1 server and some clients (may be 1 or more clients). They all should give the following output:
Starting... A B C E F ... ... Done!
They all give the above output without using multi-thread. But using multi-threading, it gives the above output only when there're 1 server and 1 client. I'm using 2 threads (1 for sending, 1 for receiving) for each Socket. That means, each client has only 2 threads for communication but the server has (2 * totalClients) threads.
I've attached my full test project. So, here I'm only showing my 2 thread classes.
ReceiveThread class: class ReceiveThread extends Thread { private ObjectInputStream receiveStream; private BlockingQueue<Character> queue = new ArrayBlockingQueue<Character>(Common.totalClients);
[Code] ....
Since I've attached my full test project, I'm not showing the other 3 classes. They are ServerMain, ClientMain and Common. If I've 2 clients to be connected, then I get the following output:
Server: (Runs first)
Starting... A Client 1 (clientID is 1): (Runs after the server)
Starting... A B B Client 2 (clientID is 2): (Runs after Client 1)
Starting... A
They are stuck at there, even no exception. Actually, the server and the clients are stuck at the line try { ch = queue.take(); } if more than 1 client are connected. It seems that all are trying to receive data. But without using the dedicated threads, they all work as expected even for more than 1 client. Why is this behaviour? How to solve it? Note that I have used the same SendThread and ReceiveThread classes by which I have succcessfully implemented P2P communication.
About my attached test project file:
It has 5 small .java files for the classes as stated above. It is currently faulty when using additional threads. You have to change clientID variable for each client (they are described inside). But it works as expected without additional threads. To test it without the additional threads:
Comment " TODO" linesUncomment the single lines just after " TODO" linesComment the additional thread construction lines (4 lines)
Currently, for a workaround, I'm not using the dedicated threads for sending and receiving data only for client-server communication in my multi-player game. But I'm still using these threads for P2P communication. I don't know why it is and how to solve it.This is the attached test project file as described above.
I am trying to make a Connect Four game with java swing, but I am getting an error with my attempt at making an multi D panel maker when I try to run it.
I have a task of returning US holiday based on the given date and this utility will be used in a multi thread environment. I have written as below, how to know if my code breaks at any given point by multiple threads
I tried to test this with few concurrent threads, and noticed that the DB call is made for the very first time or when the year being requested is not same as the cached year. But I wanted to see, if this is properly synchronizing and would not fail in any case. My intention is to make a singleton HolidayCalendar, and also synchronized well enough so that every thread using this class gets the required data without blocking each other.
My requirement is to find the line number using multiline string. Here I need to extract the string between FROM and where clause(from the below string) and need to find the line number in the file
SELECT HL.LOCATION_ID,HPS.PARTY_SITE_ID,HCAS.CUST_ACCT_SITE_ID INTO LN_SITE_LOCATION_ID,LN_LOC_PARTY_SITE_ID,LN_CUST_ACCT_SITE_ID FROM HZ_LOCATIONS HL, HZ_PARTY_SITES HPS,
I mainly would like to know is a int[4][4] or a int [4*4] is more efficient to use. Which takes more storage? Which requires more to process? that kind of stuff.
I am learning out design patterns and doing a little fun project on Model Control View (MCV). I got the concept down, it is pretty simple for the most part. However my buttons are not working.
Here is the code:
public class Controller { private Model model; private View view; Controller(Model model, View view) { this.model = model; this.view = view;
[code]....
It runs but nothing. My other questions is how can I make a box that will print the results.
Right now, i'm trying to do is when a user clicks on my GUI button, it would display a text of information on the button they selected. I'm using an arraylist of objects and i'm trying to input the function inside the mouse click function. But I'm not sure how to properly display that information. Here is my GUI code. I'm working on the raven button. I have animal interface, with a parent class of Bird, and child class of Raven. How I could display this correctly...
public class AnimalJF extends JFrame { private JPanel contentPane; private JTextArea textArea = new JTextArea(); /** * Launch the application. */ public static ArrayList<Bird> Birdlist = new ArrayList<Bird>(); public static void main(String[] args) { Birdlist.add(new Eagle());
So I have a Jframe that has a set of functions that act on a node. What I want to do is allow the user to expand the gui by creating new sets (copies) of these functions when they have more nodes.I thought of hiding extra sets and making it appear they are adding them by making them visible.
