Need help coding simple applet program

Hello I'm attempting to learn applet programming in either swing or awt. Whichever is best for current applications. I want to begin by creating my first hello world application. I want to create a simple applet that has two buttons, press button number one and the text "hello world 1" comes up somewhere on the applet, press two and "hello world 2" comes up. can anyone help me with this simple applet? Thnx in advance

http://java.sun.com/docs/books/tutorial/applet/

Similar Messages

Need Help with Simple Chat Program

Hello Guys,
I'm fairly new to Java and I have a quick question regarding a simple chat program in java. My problem is that I have a simple chat program that runs from its own JFrame etc. Most of you are probably familiar with the code below, i got it from one of my java books. In any case, what I'm attempting to do is integrate this chat pane into a gui that i have created. I attempted to call an instace of the Client class from my gui program so that I can use the textfield and textarea contained in my app, but it will not allow me to do it. Would I need to integrate this code into the code for my Gui class. I have a simple program that contains chat and a game. The code for the Client is listed below.
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.net.*;
import javax.swing.*;
public class Client
extends JPanel {
public static void main(String[] args) throws IOException {
String name = args[0];
String host = args[1];
int port = Integer.parseInt(args[2]);
final Socket s = new Socket(host, port);
final Client c = new Client(name, s);
JFrame f = new JFrame("Client : " + name);
f.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent we) {
c.shutDown();
System.exit(0);
f.setSize(300, 300);
f.setLocation(100, 100);
f.setContentPane(c);
f.setVisible(true);
private String mName;
private JTextArea mOutputArea;
private JTextField mInputField;
private PrintWriter mOut;
public Client(final String name, Socket s)
throws IOException {
mName = name;
createUI();
wireNetwork(s);
wireEvents();
public void shutDown() {
mOut.println("");
mOut.close();
protected void createUI() {
setLayout(new BorderLayout());
mOutputArea = new JTextArea();
mOutputArea.setLineWrap(true);
mOutputArea.setEditable(false);
add(new JScrollPane(mOutputArea), BorderLayout.CENTER);
mInputField = new JTextField(20);
JPanel controls = new JPanel();
controls.add(mInputField);
add(controls, BorderLayout.SOUTH);
mInputField.requestFocus();
protected void wireNetwork(Socket s) throws IOException {
mOut = new PrintWriter(s.getOutputStream(), true);
final String eol = System.getProperty("line.separator");
new Listener(s.getInputStream()) {
public void processLine(String line) {
mOutputArea.append(line + eol);
mOutputArea.setCaretPosition(
mOutputArea.getDocument().getLength());
protected void wireEvents() {
mInputField.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) {
String line = mInputField.getText();
if (line.length() == 0) return;
mOut.println(mName + " : " + line);
mInputField.setText("");

Thanks for ur help!i have moved BufferedReader outside the loop. I dont think i am getting exception as i can c the output once.What i am trying to do is repeat the process which i m getting once.What my method does is first one sends the packet to multicasting group (UDP) and other method receives the packets and prints.

Need Help with simple array program!

Hi, I have just recently started how to use arrays[] in Java and I'm a bit confused and need help designing a program.
What this program does, it reads in a range of letters specified by the user. The user then enters the letters (a, b or c) and stores these characters into an array, which the array's length is equal to the input range the user would enter at the start of the program. The program is then meant to find how many times (a,b and c) appears in the array and the Index it first appears at, then prints these results.
Here is my Code for the program, hopefully this would make sense of what my program is suppose to do.
import B102.*;
class Letters
     static int GetSize()
          int size = 0;
          boolean err = true;
          while(err == true)
               Screen.out.println("How Many Letters would you like to read in?");
               size = Keybd.in.readInt();
               err = Keybd.in.fail();
               Keybd.in.clearError();
               if(size <= 0)
                    err = true;
                    Screen.out.println("Invalid Input");
          return(size);
     static char[] ReadInput(int size)
          char input;
          char[] letter = new char[size];
          for(int start = 1; start <= size; start++)
               System.out.println("Please enter a letter (a, b or c) ("+size+" max), enter # to stop:");
               input = Keybd.in.readChar();
               while((input != 'a') && (input != 'b') && (input != 'c') && (input != '#'))
                    Screen.out.println("Invalid Input");
                    System.out.println("Please enter a letter (a, b or c) ("+size+" max, enter # to stop:");
                    input = Keybd.in.readChar();
                                while(input == '#')
                                             start == size;
                                             break;
               for(int i = 0; i < letter.length; i++)
                    letter[i] = input;
          return(letter);
     static int CountA(char[] letter)
          int acount = 0;
          for(int i = 0; i < letter.length; i++)
               if(letter[i] == 'a')
                    acount++;
          return(acount);
     static int CountB(char[] letter)
          int bcount = 0;
          for(int i = 0; i < letter.length; i++)
               if(letter[i] == 'b')
                    bcount++;
          return(bcount);
     static int CountC(char[] letter)
          int ccount = 0;
          for(int i = 0; i < letter.length; i++)
               if(letter[i] == 'c')
                    ccount++;
          return(ccount);
     static int SearchA(char[] letter)
          int ia;
          for(ia = 0; ia < letter.length; ia++)
               if(letter[ia] == 'a')
                    return(ia);
          return(ia);
     static int SearchB(char[] letter)
          int ib;
          for(ib = 0; ib < letter.length; ib++)
               if(letter[ib] == 'b')
                    return(ib);
          return(ib);
     static int SearchC(char[] letter)
          int ic;
          for(ic = 0; ic < letter.length; ic++)
               if(letter[ic] == 'c')
                    return(ic);
          return(ic);
     static void PrintResult(char[] letter, int acount, int bcount, int ccount, int ia, int ib, int ic)
          if(ia <= 1)
               System.out.println("There are "+acount+" a's found, first appearing at index "+ia);
          else
               System.out.println("There are no a's found");
          if(ib <= 1)
               System.out.println("There are "+bcount+" b's found, first appearing at index "+ib);
          else
               System.out.println("There are no b's found");
          if(ic <= 1)
               System.out.println("There are "+ccount+" c's found, first appearing at index "+ic);
          else
               System.out.println("There are no c's found");
          return;
     public static void main(String args[])
          int size;
          char[] letter;
          int acount;
          int bcount;
          int ccount;
          int ia;
          int ib;
          int ic;
          size = GetSize();
          letter = ReadInput(size);
          acount = CountA(letter);
          bcount = CountB(letter);
          ccount = CountC(letter);
          ia = SearchA(letter);
          ib = SearchB(letter);
          ic = SearchC(letter);
          PrintResult(letter, acount, bcount, ccount, ia, ib, ic);
          return;
}     Some errors i get with my program are:
When reading in the letters to store into the array, I get the last letter I entered placed into the entire array. Also I believe my code to find the Index is incorrect.
Example Testing: How many letters would you like to read? 3
Enter letter (a, b or c) (# to quit): a
Enter letter (a, b or c) (# to quit): b
Enter letter (a, b or c) (# to quit): c
It prints "There are no a's'" (there should be 1 a at index 0)
"There are no b's" (there should be 1 b at index 1)
and "There are 3 c's, first appearing at index 0" ( there should be 1 c at index 2)
The last thing is that my code for when the user enters "#" that the input of letters would stop and the program would then continue over to the counting and searching part for the letters, my I believe is correct but I get the same problem as stated above where the program takes the character "#" and stores it into the entire array.
Example Testing:How many letters would you like to read? 3
Enter letter (a, b or c) (# to quit): a
Enter letter (a, b or c) (# to quit): #
It prints "There are no a's'" (should have been 1 a at index 0)
"There are no b's"
and "There are no c's"
Can someone please help me??? or does anyone have a program simular to this they have done and would'nt mind showing me how it works?
Thanks
lou87.

Without thinking too much...something like this
for(int start = 0; start < size; start++) {
            System.out.println("Please enter a letter (a, b or c) ("+size+" max), enter # to stop:");
            input = Keybd.in.readChar();
            while((input != 'a') && (input != 'b') && (input != 'c') && (input != '#')) {
                Screen.out.println("Invalid Input");
                System.out.println("Please enter a letter (a, b or c) ("+size+" max, enter # to stop:");
                input = Keybd.in.readChar();
            if(input == '#') {
                    break;
            letter[start] = input;
        }you dont even need to do start = size; coz with the break you go out of the for loop.

Need Help w/ Java Applet Program

Hello, first time on fourms. I've taken one year of Java(Poorly instructed) and I am currently trying to build a simple program, my brother is a really good gymnast so the object of this program is two drop down menus with selections, and based on the selections, an output. It has been a while since i've done anything, i've looked for reference at old work i've done and I just have gotten lost, I just need a few pointers. I'm also having compile problems such as, "Cannot find symbol", it is frustrating me, any help would be greatly appreciated!
Here is what i've got so far, based on the above "requirements" can anyone help me out? PS. The odd names I gave them are based on another similar program I wrote a while back. Thanks again!
import javax.swing.*;
import javax.swing.border.*;
import java.awt.*;
import java.awt.event.*;
import java.lang.*;
public class gymnastics extends JFrame
private JComboBox equationTypeComboBox;
private JComboBox equationTypeComboBox2;
private JTextField answerTextField;
public gymnastics()
     setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
     setUpInfoPanel();
     setUpInfoPanel2();
     setUpEquationPanel();
setSize(300,340);
answerTextField.requestFocus();
private void setUpInfoPanel()
JPanel infoPanel = new JPanel();
infoPanel.setLayout(new BoxLayout(infoPanel, BoxLayout.Y_AXIS));
JPanel typePanel = new JPanel();
typePanel.add(new JLabel("Event type: "));
equationTypeComboBox = new JComboBox("Floor", "Pommel", "Vault", "Rings", "PBars", "High Bar");
          typePanel.add(equationTypeComboBox);
infoPanel.add(typePanel);
getContentPane().add(infoPanel, BorderLayout.NORTH);
     private void setUpInfoPanel2()
          JPanel infoPanel2 = new JPanel();
          infoPanel2.setLayout(new BoxLayout(infoPanel2, BoxLayout.Y_AXIS));
          JPanel typePanel = new JPanel();
          typePanel2.add(new JLabel("Group Code: "));
          equationTypeComboBox2 = new JComboBox("I","II","III","IV","V");
          typePanel.add(equationTypeComboBox2);
          infoPanel.add(typePanel);
          getContentPane().add(infoPanel2, BorderLayout.CENTER);
     public void setUpEquationPanel();
     equationPanel.add(new JLabel("Output: "));
     answerTextField = new JTextField();
     answerTextField = ("Test Output");
equationPanel.add(answerTextField);
getContentPane().add(equationPanel, BorderLayout.SOUTH);
          public static void main(String args[])
     new gymnastics().setVisible(true);
}

Sorry about the code problem and thanks for the encouragement, it is just a bit frustrating at times.
import javax.swing.*;
import javax.swing.border.*;
import java.awt.*;
import java.awt.event.*;
import java.lang.*;
public class gymnastics extends JFrame
private JComboBox equationTypeComboBox;
private JComboBox equationTypeComboBox2;
private JTextField answerTextField;
public gymnastics()
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setUpInfoPanel();
setUpInfoPanel2();
setUpEquationPanel();
setSize(300,340);
answerTextField.requestFocus();
private void setUpInfoPanel()
JPanel infoPanel = new JPanel();
infoPanel.setLayout(new BoxLayout(infoPanel, BoxLayout.Y_AXIS));
JPanel typePanel = new JPanel();
typePanel.add(new JLabel("Event type: "));
equationTypeComboBox = new JComboBox("Floor", "Pommel", "Vault", "Rings", "PBars", "High Bar");
typePanel.add(equationTypeComboBox);
infoPanel.add(typePanel);
getContentPane().add(infoPanel, BorderLayout.NORTH);
private void setUpInfoPanel2()
JPanel infoPanel2 = new JPanel();
infoPanel2.setLayout(new BoxLayout(infoPanel2, BoxLayout.Y_AXIS));
JPanel typePanel = new JPanel();
typePanel2.add(new JLabel("Group Code: "));
equationTypeComboBox2 = new JComboBox("I","II","III","IV","V");
typePanel.add(equationTypeComboBox2);
infoPanel.add(typePanel);
getContentPane().add(infoPanel2, BorderLayout.CENTER);
public void setUpEquationPanel();
equationPanel.add(new JLabel("Output: "));
answerTextField = new JTextField();
answerTextField = ("Test Output");
equationPanel.add(answerTextField);
getContentPane().add(equationPanel, BorderLayout.SOUTH);
public static void main(String args[])
new gymnastics().setVisible(true);
}

Need help coding simple chat client/server

I'm writing a simple chat server/client... its works fine when run on console.. but when i used Frames, AWT gui's.... it seems that the thread that is used to read the incoming message is suspended ... until i press the [send] button.. It seems to me that AWT consumes the time listening to any event.... and my thread is waiting... for the some AWT specific events to occur.....
If your interested guys.. i'm willing to post the source code.. here.

Try using the swing components. I think they are supposed to be more thread safe than awt. There is a tutorial for dealing with threads and swing:
http://java.sun.com/tutorial/uiswing/overview/threads.html
hopes this helps

Need help for writing extract program

hi
i need help for writing extract program to retriew data from legacy system.
i already developed bdc programs for me31k and me21.
my requirement is to write extract program s for those t.codes.
to retriew data from legacy system and stored in flat file.

i need help with a java program. it is a program that allows the user to enter a student's GPA, number of extracurricular activities, and number of service activities. The user can not enter a gpa above 4.0 or below 0. The user can not enter a negative number for the number of both activities. If the student meets the following criteria: 1) GPA of 3.8 or above and at least one extracurricular activity and one service activity, 2) GPA below 3.8 but at least 3.4 and a total of at least three extracurricular and service activities, 3) GPA below 3.4 but at least 3.0 and at least two extracurricular activities and three service activities, the message "Scholarship candidate" should display. If the student does not meet the criteria above, then the message"not a candidate" should display. Can you help me, please?
You haven't posted ANY 'java program' for us to help with.
The forum is NOT a coding service. It is to help you with YOUR code.
Post the code you have written and SHOW us (don't just tell us) how you compile it and execute it and the results you get. Then we can help you with any problems you are are having.
If you need help understanding just what the program should be doing you need to ask your instructor to clarify the assignment.

I need help instantly on this program please

import java.util.*;
public class D3
          private static int[] z = new int[100000];
private static int first=z[0];
          private static int last=z[n-1];
          private static int n=100000;
public static void main(String args[])
Scanner input=new Scanner(System.in);
for(int i=0;i<z.length;i++)
          z=2*i;
int seqSearch(z;50000;n); //method call 4 key where key=mid
          int binSearch(z;first;last;50000);
          int seqSearch(z;35467;n); //method call 4 key where key in the left half
          int binSearch(z;first;last;35467);
          int seqSearch(z;89703;n); //method call 4 key where key in the right half
          int binSearch(z;first;last;89703);
          public int seqSearch(int z[];int key;int n)
     long start = System.currentTimeMillis();
int count=0;
int ans=-1;
for(int i=0;i<n;i++)
if z[i]=key
count++
{ans=i
break;}
return ans;
long elapsed = System.currentTimeMillis() - start;
System.out.print("Execution Time:" + elapsed);
System.out.print("# of Basic Operations:" + count);
     public int binSearch(int z[];int first;int last;int key)
     long start = System.currentTimeMillis();
     int count=0;
     if(last<first){
     count++;
     index=-1;
     else
     count++;
     int mid=(first+last)/2
     if(ket=z[mid]{
     index=mid;
     else
     if(key<z[mid]){
     index = binSearch(z[];first;mid-1;key);
     else
     index=binSearch(z[];mid+1;last;key);
     return index;
     long elapsed = System.currentTimeMillis() - start;
     System.out.print("Execution Time:" + elapsed);
     System.out.print("# of Basic Operations:" + count);
// if anyone could tell me whats wrong with my code i'd be greatful...the program is supposed to perform binary and sequential search on a sorted array of 100000 numbers.once on an item in the middle of the array once on the right side of it and once on the left side...i also need to count the number of basic operations for the same number in both sequential and binary to see whats better.and i need to check the time...plz i need help now,,,

"Guide to a first-time poster"
you need to add exclamation marks to signify how urgent it is
e.g.
i need help instantly on this program please!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
capital letters is better
I NEED HELP INSTANTLY ON THIS PROGRAM PLEASE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
starting the italics on line 1, better again
import java.util.*;
public class D3
private static int[] z = new int[100000];
private static int first=z[0];
private static int last=z[n-1];
private static int n=100000;
public static void main(String args[])
Scanner input=new Scanner(System.in);
for(int i=0;i<z.length;i++)
z=2*i;
int seqSearch(z;50000;n); //method call 4 key where key=mid
int binSearch(z;first;last;50000);
int seqSearch(z;35467;n); //method call 4 key where key in the left half
int binSearch(z;first;last;35467);
int seqSearch(z;89703;n); //method call 4 key where key in the right half
int binSearch(z;first;last;89703);
public int seqSearch(int z[];int key;int n)
long start = System.currentTimeMillis();
int count=0;
int ans=-1;
for(int i=0;i<n;i++)
if z=key
count++
{ans=i
break;}
return ans;
long elapsed = System.currentTimeMillis() - start;
System.out.print("Execution Time:" + elapsed);
System.out.print("# of Basic Operations:" + count);
public int binSearch(int z[];int first;int last;int key)
long start = System.currentTimeMillis();
int count=0;
if(last><first){
count++;
index=-1;
else
count++;
int mid=(first+last)/2
if(ket=z[mid]{
index=mid;
else
if(key><z[mid]){
index = binSearch(z[];first;mid-1;key);
else
index=binSearch(z[];mid+1;last;key);
return index;
long elapsed = System.currentTimeMillis() - start;
System.out.print("Execution Time:" + elapsed);
System.out.print("# of Basic Operations:" + count);
and what about the dukes, offer 10 (never to be awarded, of course)
do this, then sit back and watch the replies roll in.

Need help getting my applet to run..

Hi, I am having the utmost trouble getting my applet to run. First I spent a month correcting syntax and other errors generated during compile. Now I find myself spending another month getting the compiled product to run. I don't care if the screen is completely blank and my logic is all messed up, I don't mind logic debugging. My applet just will not run at all, it won't even initialize.
First when I tried to run my applet in Internet Explorer I got the following error in the statusbar:
"load: tsorgi5 can't be instantiated"
So, I researched that error message, and the solution appeared to be that I would need to use the Java Plug-In. So, I use that and now I find this message in the statusbar:
"exception: null."
That happens when the text "Loading Java Applet ..." is in the centre of the applet, and Internet Explorer acts like it is still doing something no matter how long I wait.
I tried researching this, but only found "exception: null" with other things after the text "null."
In Forte, when I choose "Execute" I get the following in the Output Window, I/O tab:
java.lang.NoSuchMethodError: main
Exception in thread "main"
I would assume it expects me to add a method "main()," but I also get that same message with a different applet (which doesn't have a method "main()") which runs perfectly fine.
I usually try to solve many of my problems myself, but with this one I have no idea where to start looking for answers. I'm relatively new to Java, been using Java for only half a year, so this particular problem is like looking for a four-leaf clover in the streets of New York City..
I'm going to be chopping my applet into pieces, having a separate class file for each major engine. (It is a role-playing game, so I'll separate battle engine from cut-scene engine from world exploration engine etc..) Hopefully I will be able to narrow down my search for what is causing me all of these problems. Then once I solve my problems I can piece everything back together.
In the meantime, I am hoping that some of you could help me out so that I may know what I am looking for.
Thank You for your time,
-Tony Slater

Ah.. Forte is still a bit confusing to me, I have not and probably will not take the time to learn much about Forte, as the only real reason I use it is because unlike wordpad, I can see line numbers. =] Very helpful with my program being the size that it is.
I do not think that the simple applet idea will be of much use, because one of my earlier applet projects (a main menu for my current project) which I mentioned above as another applet without a main() method which worked perfectly fine is very simple. Although I will try it anyway, as it could help and you are most likely much more experienced than I. =]
Okay, I typed the following in the Dos Prompt:
appletviewer TestApplet.class
..It printed a blank line, paused a little bit, then brought me back to the prompt, just like running a dos program that does not give any output. I'm not sure, but I would assume it should print a line containing the text "Here?" I have not used appletviewer before, so I do not know what it is supposed to do. =P
I have already tried using System.out.println, but the problem occours even before the applet is started. I'll try enabling the Java Console first thing tomorrow morning, since a restart is required when enabling it.
Now, I would be happy to post some code, but I'm not sure it would be best to post the code when my program is 2814 lines.. although 800 lines are probably comments, and most of those comments are probably irrelevant. Also I can sometimes be a messy coder. Although I can post some general information and can probably (with a little work) post an "outline" of the code.
Since it is getting late I'll just post some portions of code which hopefully will prove important.
// Import Packages
import java.awt.Graphics;
import java.awt.Color;
import java.awt.*;
import java.applet.*;
import java.lang.System;
import java.lang.reflect.Array;
import java.lang.Math;
import java.lang.Double;
import java.math.*;
import java.util.Random;
import java.io.*;
variable/object types created and/or declared between "public class.." and "public void init()...":
int
byte[]
String
RandomAccessFile
int[][]
double
int[]
double[][][]
Random
Image
int[][][]
arrays are filled in the init() method.
public String getIniStrValue(String iniFile, String iniGroup, String iniItem) // Used for retrieving information from the game's external file system.
another method getIniIntValue(int, String, String, String) is used for int values stored in external files.
Within public void paint(), gameplay modes are detected and dealt with accordingly. With Cut-Scenes, proper charecter images and text is displayed, all cut-scene information is stored externally. Other modes do virtually the same, display graphics and text based on internal game data or un-changing external data files.
Within public void mouseClick(), in certain modes of the game the mouse click will trigger a change no matter where the user clicked (such as cut-scenes, to advance to the next line of dialog), or different variables are set depending on where the user clicked. (What I like to call.. custom buttons) At the end of the method repaint(); is used, and the paint() method will alter the screen according to any changes that may have happened.
public void charAttack() is a method called to handle battle equations when a playable and controllable charecter is making a move. It will detect the current charecter, detect the move being made by the charecter (attack, special move, magic, etc) and will change any variables accordingly and will then use repaint(); so that the player may know what has happened. (Whether or not attack was successful, how many HP the enemy lost, etc)
public void loadBattle() is called when the charecter encounters an enemy. It will load possible enemies of the current part of the world being explored, select one, then load that enemy's "stats" from external game data files, and will then specify the new mode (Battle Menu, where the player chooses the moves to be made for the turn) by setting the int value "Mode." repaint(); is then called and it will paint the battle menu.
public boolean keyDown() is of course used to detect keyboard events. In world exploration, the charecter will be moved accordingly. In modes such as cut-scenes, a variable will be changed to advance to the next line of speech. In menus, the keyboard events are used to switch between options. repaint(); is used to update the screen accordingly.
Well, even though I very briefly summarized the code, it appears to have taken half an hour to do. I'll be getting some sleep in a few minutes, and when I wake up tomorrow morning I hope to both see and make some progress on solving this problem.
Thank You,
-Tony Slater.

Need help getting my applets to work on web pages!

I've been trying to get it to work for a while now, and I no idea why it won't work! I've tried all kinds of things to get it to work, but it still won't work. All I want to do is make a simple applet, don't care what it does, and put it on a web page.
Here is my HTML code:
<applet code=?Slime2P.class? height=?300? width=?400? codebase=?http://www.spinarcade.com/tests?>
</APPLET>
Here is a link to what happens:
[http://www.spinarcade.com/tests/duk.html|http://www.spinarcade.com/tests/duk.html]
Here is the errors:
load: class ?Slime2P.class? not found.
java.lang.ClassNotFoundException: ?Slime2P.class?
     at sun.applet.AppletClassLoader.findClass(Unknown Source)
     at java.lang.ClassLoader.loadClass(Unknown Source)
     at sun.applet.AppletClassLoader.loadClass(Unknown Source)
     at java.lang.ClassLoader.loadClass(Unknown Source)
     at sun.applet.AppletClassLoader.loadCode(Unknown Source)
     at sun.applet.AppletPanel.createApplet(Unknown Source)
     at sun.plugin.AppletViewer.createApplet(Unknown Source)
     at sun.applet.AppletPanel.runLoader(Unknown Source)
     at sun.applet.AppletPanel.run(Unknown Source)
     at java.lang.Thread.run(Unknown Source)
It works fine when I run the applet in eclipse, and I've tried many different applets. I tried using a cool program I wanted to put online first, then I made a simple program to try, and then I even downloaded the file from a tutorial and didn't edit it at all... nothing works!
Here's code from one of the applets (Simple applet with green lines):
import java.applet.*;
import java.awt.*;
public class Duck extends Applet {
int width, height;
public void init() {
width = getSize().width;
height = getSize().height;
setBackground( Color.black );
public void paint( Graphics g ) {
g.setColor( Color.green );
for ( int i = 0; i < 10; ++i ) {
g.drawLine( width, height, i * width / 10, 0 );
I have all the .class file and the html page in the same place (http://www.spinarcade.com/tests).
Thank you for your help! It is most likely something simple...
Edited by: Donv7 on Jul 17, 2008 2:27 PM

Here is your html:
<HTML>
<HEAD>
<TITLE>Duk!</TITLE>
</HEAD>
<body bgcolor="#DAE9F3">
<center>
<applet code=?Slime2P.class? height=?300? width=?400?>
</APPLET>
ducks these dayz...<br>
codebase=?http://www.spinarcade.com/tests?<br>
C:\Documents and Settings\Don\Desktop<br>
http://www.spinarcade.com/tests<br>
</center>
</BODY>
</HTML>Look carefully at the double quotes surrounding the red text (bgcolor).
Look at the double quotes used in the applet tag now!!!

Need Help With D&D Program

Hi, I'm not sure if I'm allowed to post questions on this forum but I can't find anywhere to talk to helpful people about programming.
I'm making a dnd interface for JComponents. So far I've made a simple program that has a Component that can be lifted from a container and braught to the glass pane then later moved to anywhere on the screen and dropped into the container below it. Here's where my problems come:
1) Rite now my 'Movable Component' is a JPanel which is just colored in. I want to either take a Graphic2d from a JComponent/Component and draw it on the JPanel or change the JPanel to the component I want to paint and disable the component.
The problem with getting the Graphics2d is that if the component isn't on the screen it doesn't make a graphic object. I tried messing with the ui delicate and overriding parental methods for paintComponent, repaint, and that repaintChildren(forget name) but I haven't had luck getting a good graphics object. I was thinking of, at the beginning of running the program, putting 1 of each component onto the screen for a second then removing it but I'd rather not. I'd also like to change the graphics dynamicly if someone stretches the component there dropping and what not.
The problem with disabling is that it changes some of the visual features of Components. I want to be able to update the Component myself to change how it looks and I don't want disabling to gray out components.
I mainly just dont want the components to do any of there normal fuctions. This is for a page builder, by the way.
Another problem I'm having is that mouseMotionListener is allowing me to select 2 components that are on top of one another when there edges are near each other. I don't know if theres a fix to this other than changing the Java Class.
My next problem is a drop layout manager, but I'm doing pretty good with that rite now. It'll problem just move components out of the way of the falling component.
One last thing I need help with is that I don't want the object that's being carried to go across the menu bar and certain areas. When I'm having the object being carried I have it braught up to the glass pane which allows it to move anywhere. Does anyone have any idea how I could prevent the component from being over the menu bars and other objects? I might have to make 1 panel is the movable area that can then be broken down into the 'component bank', 'building page' and whatever else I'm gonna need.
This is all just test code to get together for when I make the real program but I need to make sure it'll be possible without a lot of hacking of code.
Sorry for the length. Thanks for any help you can give.

The trick to making viewable components that have no behaviour, is to render them onto an image of some sort (eg a BufferedImage). You can then display the Image on a JLabel that can be dragged around the desktop.
Here is a piece of code that does the component rendering for you. This particular example uses a fixed component size, but you can modify that as you choose of course...public class JComponentImage
     private static GraphicsConfiguration gConfig;
     private static Dimension compSize = new Dimension(80, 22);
     private static Image image = null;
     public static Image getImage(Class objectClass)
          if (gConfig == null)
               GraphicsEnvironment gEnv = GraphicsEnvironment.getLocalGraphicsEnvironment();
               GraphicsDevice gDevice = gEnv.getDefaultScreenDevice();
               gConfig = gDevice.getDefaultConfiguration();
          image = gConfig.createCompatibleImage(compSize.width, compSize.height);
          JComponent jc = (JComponent) ObjectFactory.instantiate(objectClass);
          jc.setSize(compSize);
          Graphics g = image.getGraphics();
          g.setColor(Color.LIGHT_GRAY);
          g.fillRect(0, 0, compSize.width, compSize.height);
          g.setColor(Color.BLACK);
          jc.paint(g);
          return image;
}And here is the class that makes the dragable JLabel using the class above...public class Dragable extends JLabel
     private static DragSource dragSource = DragSource.getDefaultDragSource();
     private static DragGestureListener dgl = new DragMoveGestureListener();
     private static TransferHandler th = new ObjectTransferHandler();
     private Class compClass;
     private Image image;
     Dragable(Class compClass)
          this.compClass = compClass;
          image = JComponentImage.getImage(compClass);
          setIcon(new ImageIcon(image));
          setTransferHandler(th);
          dragSource.createDefaultDragGestureRecognizer(this,
                                                      DnDConstants.ACTION_COPY,
                                                      dgl);
     public Class getCompClass()
          return compClass;
}Oh and here is ObjectFactory which simply instantiates Objects of a given class and sets their text to their classname (very crudely)...public class ObjectFactory
     public static Object instantiate(Class objectClass)
          Object o = null;
          try
               o = objectClass.newInstance();
          catch (Exception e)
               System.out.println("ObjectFactory#instantiate: " + e);
          String name = objectClass.getName();
          int lastDot = name.lastIndexOf('.');
          name = name.substring(lastDot + 1);
          if (o instanceof JLabel)
               ((JLabel)o).setText(name);
          if (o instanceof JButton)
               ((JButton)o).setText(name);
          if (o instanceof JTextComponent)
               ((JTextComponent)o).setText(name);
          return o;
}Two more classes required by this codepublic class ObjectTransferHandler extends TransferHandler {
     private static DataFlavor df;
      * Constructor for ObjectTransferHandler.
     public ObjectTransferHandler() {
          super();
          try {
               df = new DataFlavor(DataFlavor.javaJVMLocalObjectMimeType);
          } catch (ClassNotFoundException e) {
               Debug.trace(e.toString());
     public Transferable createTransferable(JComponent jC) {
          Transferable t = null;
          try {
               t = new ObjectTransferable(((Dragable) jC).getCompClass());
          } catch (Exception e) {
               Debug.trace(e.toString());
          return t;
     public int getSourceActions(JComponent c) {
          return DnDConstants.ACTION_MOVE;
     public boolean canImport(JComponent comp, DataFlavor[] flavors) {
          if (!(comp instanceof Dragable) && flavors[0].equals(df))
               return true;
          return false;
     public boolean importData(JComponent comp, Transferable t) {
          JComponent c = null;
          try {
               c = (JComponent) t.getTransferData(df);
          } catch (Exception e) {
               Debug.trace(e.toString());
          comp.add(c);
          comp.validate();
          return true;
public class ObjectTransferable implements Transferable {
     private static DataFlavor df = null;
     private Class objectClass;
     ObjectTransferable(Class objectClass) {
          try {
               df = new DataFlavor(DataFlavor.javaJVMLocalObjectMimeType);
          } catch (ClassNotFoundException e) {
               System.out.println("ObjectTransferable: " + e);
          this.objectClass = objectClass;
      * @see java.awt.datatransfer.Transferable#getTransferDataFlavors()
     public DataFlavor[] getTransferDataFlavors() {
          return new DataFlavor[] { df };
      * @see java.awt.datatransfer.Transferable#isDataFlavorSupported(DataFlavor)
     public boolean isDataFlavorSupported(DataFlavor testDF) {
          return testDF.equals(df);
      * @see java.awt.datatransfer.Transferable#getTransferData(DataFlavor)
     public Object getTransferData(DataFlavor arg0)
          throws UnsupportedFlavorException, IOException {
          return ObjectFactory.instantiate(objectClass);
}And of course the test class:public class DragAndDropTest extends JFrame
     JPanel leftPanel = new JPanel();
     JPanel rightPanel = new JPanel();
     Container contentPane = getContentPane();
     Dragable dragableJLabel;
     Dragable dragableJButton;
     Dragable dragableJTextField;
     Dragable dragableJTextArea;
      * Constructor DragAndDropTest.
      * @param title
     public DragAndDropTest(String title)
          super(title);
          dragableJLabel = new Dragable(JLabel.class);
          dragableJButton = new Dragable(JButton.class);
          dragableJTextField = new Dragable(JTextField.class);
          dragableJTextArea = new Dragable(JTextArea.class);
          leftPanel.setBorder(new EtchedBorder());
          BoxLayout boxLay = new BoxLayout(leftPanel, BoxLayout.Y_AXIS);
          leftPanel.setLayout(boxLay);
          leftPanel.add(dragableJLabel);
          leftPanel.add(dragableJButton);
          leftPanel.add(dragableJTextField);
          leftPanel.add(dragableJTextArea);
          rightPanel.setPreferredSize(new Dimension(500,500));
          rightPanel.setBorder(new EtchedBorder());
          rightPanel.setTransferHandler(new ObjectTransferHandler());
          contentPane.setLayout(new BorderLayout());
          contentPane.add(leftPanel, "West");
          contentPane.add(rightPanel, "Center");
     public static void main(String[] args)
          JFrame frame = new DragAndDropTest("Drag and Drop Test");
          frame.pack();
          frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
          frame.setVisible(true);
}I wrote this code some time ago, so it won't be perfect but hopefully will give you some good ideas.
Regards,
Tim

Need help with simple problem.......

Hello, I'm fairly new to Java, taking my first year in it. I have a little applet that I have to write up but I'm having some difficulties. Someone please help :)
OBJECTIVE: Print out the following using a FOR loop.
OUTPUT:
JavaProgramming
JavaProgramming
JavaProgramming
JavaProgramming
JavaProgramming
I am really having trouble doing the loop and spacing, so that it would have "JavaProgramming" appear 5 times and automatically indent 2 spaces everytime. I've done a "HSA" Console Program (NOT APPLET) where there are 5 words that are not spaced but when I try to do the same in an applet, it simply wont repeat in the loop. Below is the program where there are 5 words WITHOUT spacing in my applet program, I don't know how to repeat it 5 times and have it space 2 times everytime :(
public class Test extends Applet
    // Place instance variables here
    public void init ()
    } // init method
    public void paint (Graphics g)
        for (int i = 0 ; i < 5 ; i++)
            g.drawString ("JavaProgramming", 20, 20);
    } // paint method
} // Test classThis will only show "JavaProgramming" once when i run the program. I need it to show 5 times, with 2 spaces indented every time!

this:
g.drawString ("JavaProgramming", 20, 20);
probably needs to be something like:
g.drawString("JavaProgramming", 20+(i*10), 20+(i*10));
i.e: increase x and y pos for each iteration.

Need help with spell checker program

Hi
I am writing a spell checker program and need help for a simple logic.I have "List" of correctly spelled words and a String array of wrong spelled words.How can I compare both and tell that for eg xyz word is not spelled correctly.

BigDaddyLoveHandles wrote:
To learn more about Map, take the collection tutorial: [http://java.sun.com/docs/books/tutorial/collections/index.html]
(Actually, to me it sounds like you have a Set of correctly spelled words and another Set of words which may or may not be correctly spelled, and you want the difference...)That is what it sounds like to me also, and that is easy.
JSG

Help with simple applet - dragging box

Hi I need help with a simple applet concept.
I have a picture drawn in the background, but I need to draw a square and resize it when I drag.
So with the picture in the background I click, drag the mouse, and it draws a rectangle from the starting point to where the mouse is while the mouse is clicked.
The only problem is I can't figure out how to do this without redrawing the whole picture. If I don't repaint, it just keeps stretching around rectangles and leaving them there.
I don't really need exact code, just an idea on how to do this without repainting the background every time the mouse is moved (because the picture in the background is complicated to draw and takes like a second).
Thanks
[nvm, found out about xormode]
Edited by: BugMenOTdhzj on Nov 30, 2009 4:47 PM

BugMenOTdhzj wrote:
..the picture in the background is complicated to draw and takes like a second).Paint the 'picture in the background' to a BufferedImage, then when it comes to paint()/paintComponent(), draw the BI to the Graphics object (clipped, if necessary (1)), then draw the rectangle to the Graphics object. This would be further optimised at time of rendering, by drawing both the 'picture in the background' BI and rectangle to a second BI, and finally writing that 2nd BI to the Graphics object.
1) There are potentially other improvements that can be made, particularly with clipping, but I suspect if you try as I suggested, the rendering will be very quick and responsive. I have 40 FPS sound trace animations that do a great deal more on each call to paintComponent(), before bursting the final BI to screen.

Need help with my addressbook program

hi,
i need help with my program here. this one should works as:
- saves user input into a txt file
- displays name of the saved person on the jlist whenever i run the program
- displays info about the person when clicked via textboxes given by reading the txt file where the user inputs are
- should scroll when the list exceeds the listbox
import java.awt.event.*;
import java.awt.*;
import javax.swing.*;
import javax.swing.JList;
import java.awt.event.ActionListener;
import java.io.*;
import javax.swing.event.*;
import java.io.FilterInputStream;
public class AddressList extends JPanel implements ActionListener
     JTextField txt1 = new JTextField();
     JTextField txt2 = new JTextField();
     JTextField txt3 = new JTextField();
     DefaultListModel mdl = new DefaultListModel();
     JList list = new JList();
     JScrollPane listScroller = new JScrollPane(list);
     ListSelectionModel listSelectionModel;
     File fob = new File("Address3.txt");
     String name;
     char[] chars;
     public void ListDisplay()
          try
               RandomAccessFile rand = new RandomAccessFile(fob,"rw");
               BufferedReader br = new BufferedReader(new FileReader("Address3.txt"));
               if(fob.exists())
                     while((name = rand.readLine()) != null)
                          chars = name.toCharArray();
                          if(chars[0] == '*')
                               mdl.addElement(name);
                               list.setModel(mdl);
                          if(chars[0] == '#')
                               continue;
                else
                    System.out.println("No such file..");
          catch(IOException a)
                     System.out.println(a.getMessage());
     public AddressList()
          this.setLayout(null);
          listSelectionModel = list.getSelectionModel();
        listSelectionModel.addListSelectionListener(new ListInfo());
          list.setBounds(10,40,330,270);
          listScroller.setBounds(320,40,20,100);
          add(list);
          add(listScroller);
          JLabel lbl4 = new JLabel("Name: ");
          lbl4.setBounds(400,10,80,30);
          add(lbl4);
          JLabel lbl5 = new JLabel("Cellphone #: ");
          lbl5.setBounds(400,50,80,30);
          add(lbl5);
          JLabel lbl6 = new JLabel("Address: ");
          lbl6.setBounds(400,90,80,30);
          add(lbl6);
          JLabel lbl7 = new JLabel("List ");
          lbl7.setBounds(10,10,100,30);
          add(lbl7);
          txt1.setBounds(480,10,200,30);
          add(txt1);
          txt2.setBounds(480,50,200,30);
          add(txt2);
          txt3.setBounds(480,90,200,30);
          add(txt3);
          JButton btn1 = new JButton("Add");
          btn1.setBounds(480,130,100,30);
          btn1.addActionListener(this);
          btn1.setActionCommand("Add");
          add(btn1);
          JButton btn2 = new JButton("Save");
          btn2.setBounds(480,170,100,30);
          btn2.addActionListener(this);
          btn2.setActionCommand("Save");
          add(btn2);
          JButton btn3 = new JButton("Cancel");
          btn3.setBounds(480,210,100,30);
          btn3.addActionListener(this);
          btn3.setActionCommand("Cancel");
          add(btn3);
          JButton btn4 = new JButton("Close");
          btn4.setBounds(480,250,100,30);
          btn4.addActionListener(this);
          btn4.setActionCommand("Close");
          add(btn4);
     public static void main(String[]args)
          JFrame frm = new JFrame("Address List");
          AddressList panel = new AddressList();
          frm.getContentPane().add(panel,"Center");
          frm.setSize(700,350);
          frm.setVisible(true);
          panel.ListDisplay();
     public void actionPerformed(ActionEvent e)
          String cmd;
          cmd = e.getActionCommand();
          if(cmd.equals("Add"))
               txt1.setText("");
               txt2.setText("");
               txt3.setText("");
          else if(cmd.equals("Save"))
               mdl.addElement(txt1.getText());
               list.setModel(mdl);
               try
               RandomAccessFile rand = new RandomAccessFile(fob,"rw");
               BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
               LineNumberReader line = new LineNumberReader(br);
                if(fob.exists())
                          rand.seek(fob.length());
                          rand.writeBytes("* " + txt1.getText());
                          rand.writeBytes("\r\n" + "# " + txt2.getText());
                          rand.writeBytes("\r\n" + "# " + txt3.getText() + "\r\n");
                else
                     System.out.println("No such file..");
                    txt1.setText("");
                    txt2.setText("");
                    txt3.setText("");
                catch(IOException a)
                     System.out.println(a.getMessage());
          else if(cmd.equals("Cancel"))
               txt1.setText("");
               txt2.setText("");
               txt3.setText("");
          else if(cmd.equals("Close"))
               System.exit(0);
class ListInfo implements ListSelectionListener
     public void valueChanged(ListSelectionEvent e)
          ListSelectionModel lsm = (ListSelectionModel)e.getSource();
          int minIndex = lsm.getMinSelectionIndex();
        int maxIndex = lsm.getMaxSelectionIndex();
          try //*this one should display the info of the person whenever i click the person's name at the list box via textbox.. but i cant seem to get it right since it always display the info of the first person inputed.. i tried to get the program to display them whenever it reads lines with * on them....
               File fob = new File("Address3.txt");
               RandomAccessFile rand = new RandomAccessFile(fob,"rw");
               BufferedReader br = new BufferedReader(new FileReader("Address3.txt"));
               LineNumberReader line = new LineNumberReader(br);
               if(fob.exists())
                          for(int i = minIndex; i<=maxIndex; i++)
                               if(lsm.isSelectedIndex(i))
                                    while((name = rand.readLine()) != null)
                                         chars = name.toCharArray();
                                         if(chars[0] == '#')
                                              continue;
                                         if(chars[0] == '*')
                                              txt1.setText(rand.readLine());
                                             txt2.setText(rand.readLine());
                                             txt3.setText(rand.readLine());
                else
                          System.out.println("No such file..");
          catch(IOException a)
                     System.out.println(a.getMessage());
}the only problem now is about how it should display the right info about the person whenever i click its name on the list.. something about file reading or something, i just cant figure it out.
and also about how to make it scroll once it exceeds the list.. i cant make it work, maybe something about wrong declaration..
thanks in advance..
Edited by: syder on Mar 14, 2008 2:26 AM

Like said before, do one thing at a time. At startup, something like:
//put all the content in a list
ArrayList<String> lines = new ArrayList<String>();
while(String line=rand.readLine()!=null) {
    lines.add(line);
}If you follow the good advice to create a class to encapsulate the entries, you could populate a list of such entries like this:
static final int ENTRY_SIZE = 3;//you have 3 fields now, better to have a constant if that changes
ArrayList<Entry> entries = new ArrayList<Entry>();
for(int i=0; i<lines.size(); i+=ENTRY_SIZE) {
    Entry entry = new Entry(lines.get(i), lines.get(i+1), lines.get(i+2);
    entries.add(newEntry);
}You could also do both of the above in one run, but I think you will understand better what's happening if you do one thing at a time.
If you don't want to put the entries in an encapsulating class, you can still access this without looping:
int listStartIdx = <desired_entry_index>*ENTRY_SIZE;
String att1 = lines.get(listStartIdx).substring(1);
String att2 = lines.get(listStartIdx+1).substring(1);
String att3 = lines.get(listStartIdx+2).substring(1);

Need help with advanced applet

I need help with designing an applet as follows. Can someone give me a basic layout of code and material so i can fill in the rest or at leats give me some hints so i can get started since i am like no good at applets.
Design and implement an applet that graphically displays the processing
of a selection sort. Use bars of various heights to represent
the values being sorted. Display the set of bars after each swap. Put
a delay in the processing of the sort to give the human observer a
chance to see how the order of the values changes.
heres a website that does something similar
http://www.cs.ubc.ca/spider/harrison/Java/sorting-demo.html

elasolova wrote:
i will not help you this time. but if you buy me a candy maybe i can reconsider the issue. :PI suggest an all-day sucker.

Need help coding simple applet program

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