Nick de Waal

Thanks Kemal,

That's what I needed to know, I did not even realize the build command would create the jar file (oh man I have lots to learn)
I don't have enough experience yet
thanks for your help

Hi Kemal,

Sorry I am finding it hard to explain this, I bought a small application off someone and he sent me it in jar file but he also sent me the source code.
My idea was to replicate the program to see if I could do it.
But now, I only want to change some parts to it so I was hoping there was a way I could open the program in netbeans and edit the source code and so on.
So I guess I could just open all the source code in netbeans and then change that and save it as a new project.
I just wanted to learn from it but because it has database as well it has now become a little daunting to me as it above my expertise.
But I will try and dissect it.

thank you

Hi all,

I was hoping that someone would be able to point out a guide for me that will show/teach me how I can

open a Jar file with Netbeans

edit it

and then package it again

I tried opening it by making a new project and adding the Jar file to the library but my changes do not save.
I realize I should know this and it may well be rather simple but for the likes of me I have not yet needed to do this
(I am looking through my course materials and cannot find the answer, it does teach how to make a project in netbeans and then make that a jar file, but nothing about changing a Jar file in netbeans.

any help or links would help me considerably

Thanks Bear,

I should of mentioned that I am not a young student, I am nearing my 40's and this is a career change so I do have experience as an employee, just none in IT.
not sure if that will make a difference

Hi all,

I'm a couple of weeks away from graduating and have been offered a job as a test analyst,
I have searched the net to get an idea of what the job involves but from what I see I am worried I don't have the skills to fulfill this role.
After speaking to the job placement adviser he said they will train me and that the most important skill I need is communication.
I am not confident that with the limited IT training I have received in the last year that I am capable of doing the job.

I was wondering if anyone could ease my worries and let me know how easy the job is

Yong Lee wrote:So I'm a little stumped...the following code produces this output:

triangle 0, area = 4.0
triangle 1, area = 10.0
triangle 2, area = 18.0
triangle 3, area = 28.0
y = 4, t5 area = 343

class Triangle { double area; int height; int length; public static void main (String[] args) { int x = 0; Triangle[] ta = new Triangle[4]; while (x < 4) { ta[x] = new Triangle(); ta[x].height = (x + 1) * 2; ta[x].length = x + 4; ta[x].setArea(); System.out.print("triangle " +x+ ", area"); System.out.println(" = " + ta[x].area); x = x + 1; }//close while int y = x; x = 27; Triangle t5 = ta[2]; ta[2].area = 343; System.out.print("y = " +y); System.out.println(", t5 area = " +t5.area); }//close main void setArea() { area = (height * length) / 2; }//close setArea() }//close class
What has me stumped is the last line of output...I understand that both t5 and ta[2] are pointing to the same Triangle object, and that by setting ta[2].area = 343, t5.area will also = 343. But where does "y = 4" come from - if y = x, and x is set as 27, where is the value changed to 4? Any help would be appreciated, thanks!
[ May 26, 2008: Message edited by: Campbell Ritchie ]

I realize this is an old post but I run the exact same code as above (chapter 3 HeadFirstJava),
and I receive the following :
triangle.java:19: error: cannot find symbol Triangle t5 = new ta[2]; ^ symbol: class ta location: class Triangle triangle.java:19: error: incompatible types Triangle t5 = new ta[2]; ^ required: Triangle found: ta[] 2 errors

I have these batch files :

1:@echo off cd /d %~dp0 call "C:\JavaPrograms\source\source.bat" Pause echo "Program Executed"

2:@echo off cd /d %~dp0 ECHO. echo ************************************************** ************ dir C:\JavaPrograms\source\*.java ECHO. echo ************************************************** ************ ECHO. set /p Name=Enter one Java file name from above list for execution: javac -d ..\classes %Name%.java call C:\JavaPrograms\classes\classes.bat %1 %Name% echo "Successfully Executed"

3:@echo off cd /d %~dp0 echo Name=%Name% echo Output of the Program echo --------------------- java %Name% call "C:\Documents and Settings\Administrator\Desktop\RunJava.bat"

which saves me time, but I was wondering what could I change or need to change in order to do the same thing for two classes in the same package?

Hi Henry,

Thank you for taking the time for the explanation, as with most newbies (I'm guessing) we don't use the command line enough,
I am learning a little batch programming now, so that I can be more independent.

Thanks again.

Henry that's it!!

Thank you,
if I may ask, would you be able to give me a small explanation as to what is going on? I mean, using the "." instead of what I was doing.

Or maybe point me to an explanation on the web.
It would be much appreciated
thanks again

Hi Henry,
Actually I did mention it although I was rather vague, my apologies,
so here is a copy of the code as it stands:

package com.headfirst.game; public class GuessGame { Player p1; Player p2; Player p3; //three instance variables public void startGame() { p1 = new Player();// create three player objects and assign them to the three player instance variables p2 = new Player(); p3 = new Player(); int guessp1 = 0;//declare three variables to hold the three guesses the players make int guessp2 = 0; int guessp3 = 0; boolean p1isRight = false;//declare three variables to hold true or false based on answer boolean p2isRight = false; boolean p3isRight = false; int targetNumber = (int) (Math.random() * 10);//make a target number that the players have to guesse System.out.println("I'm thinking of a number between 0 and 9..."); while (true) { System.out.println("Number to guess is " + targetNumber); p1.guess();// call each players guess method p2.guess(); p3.guess(); guessp1 = p1.number; System.out.println("Player one guessed " + guessp1); guessp2 = p2.number; System.out.println("Player two guessed " + guessp2); guessp3 = p3.number; System.out.println("Player three guessed " + guessp3); if (guessp1 == targetNumber) { p1isRight = true; } if (guessp2 == targetNumber) { p2isRight = true; } if (guessp3 == targetNumber) { p3isRight = true; } if (p1isRight || p2isRight || p3isRight) { System.out.println("We have a winner!"); System.out.println("Player one got it right? " + p1isRight); System.out.println("Player two got it right? " + p2isRight); System.out.println("Player three got it right? " + p3isRight); System.out.println("Game Over!"); break;//game over, so break out of loop } else { //we must keep going caUSE nobody got it right System.out.println("Players will have to try again."); } } } }

package com.headfirst.game; public class Player { int number = 0;//where the guess goes public void guess() { number = (int) (Math.random() * 10); System.out.println("I'm guessing " + number); } }

package com.headfirst.game; public class GameLauncher { public static void main (String[] args) { GuessGame game = new GuessGame(); game.startGame(); } }

I have tried your suggestion and receive the exact same error as above:

I will post exactly what I am doing, so this way, I will hope to find out what I am doing wrong:

C:\Users\Sonny\Documents\Head1stJava\test>javac -d ./classes/ ./src/com/headfirst/game/*.java C:\Users\Sonny\Documents\Head1stJava\test>cd classes C:\Users\Sonny\Documents\Head1stJava\test\classes>cd src The system cannot find the path specified. C:\Users\Sonny\Documents\Head1stJava\test\classes>cd com C:\Users\Sonny\Documents\Head1stJava\test\classes\com>cd headfirst C:\Users\Sonny\Documents\Head1stJava\test\classes\com\headfirst>cd game C:\Users\Sonny\Documents\Head1stJava\test\classes\com\headfirst\game>java GameLauncher Exception in thread "main" java.lang.NoClassDefFoundError: GameLauncher (wrong name: com/headfirst/game/GameLauncher) at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:791) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) at java.net.URLClassLoader.defineClass(URLClassLoader.java:449) at java.net.URLClassLoader.access$100(URLClassLoader.java:71) at java.net.URLClassLoader$1.run(URLClassLoader.java:361) at java.net.URLClassLoader$1.run(URLClassLoader.java:355) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:354) at java.lang.ClassLoader.loadClass(ClassLoader.java:423) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308) at java.lang.ClassLoader.loadClass(ClassLoader.java:356) at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:480)

Steven Bruton wrote:You have 6 compile errors in your code, that is why it will not compile.

Just some spelling errors;
The boolean p3isRIght should be p3isRight,
You made a call to guesse() 3 times but the method name is guess().

Hi Steven,

Thank you,
yes you are right and I should be banned for posting that code without checking!
but I did fix up those errors (I just have not posted the fixed code.

I actually reverted back to netbeans to test my code and it works fine:
Result:

run:
I'm thinking of a number between 0 and 9...
Number to guess is 1
I'm guessing 6
I'm guessing 3
I'm guessing 2
Player one guessed 6
Player two guessed 3
Player three guessed 2
Players will have to try again.
Number to guess is 1
I'm guessing 3
I'm guessing 0
I'm guessing 1
Player one guessed 3
Player two guessed 0
Player three guessed 1
We have a winner!
Player one got it right? false
Player two got it right? false
Player three got it right? true
Game Over!
BUILD SUCCESSFUL (total time: 1 second)

So it has to be how I am trying to compile it on the command line
I found this site http://javaworkshop.sourceforge.net/chapter3.html and have been trying to follow it by making the test folder etc.
I am still having no luck but give me a few moments and I will post the errors I am getting.

Stephan van Hulst wrote:You probably haven't specified the classpath, so the compiler doesn't know where to look for game\GuessGame.java.

In the command line, go to the folder that contains the game folder, and try: "javac -cp . game\GuessGame.java"

I tried this already having found it on another post, but unfortunately I still receive similar errors:

C:\Users\Sonny\Documents\Head1stJava\src>javac -cp . game\GuessGame.java
game\GuessGame.java:24: error: cannot find symbol
p1.guesse();// call each players guess method
^
symbol: method guesse()
location: variable p1 of type Player
game\GuessGame.java:25: error: cannot find symbol
p2.guesse();
^
symbol: method guesse()
location: variable p2 of type Player
game\GuessGame.java:26: error: cannot find symbol
p3.guesse();
^
symbol: method guesse()
location: variable p3 of type Player
game\GuessGame.java:46: error: cannot find symbol
p3isRight = true;
^
symbol: variable p3isRight
location: class GuessGame
game\GuessGame.java:49: error: cannot find symbol
if (p1isRight || p2isRight || p3isRight) {
^
symbol: variable p3isRight
location: class GuessGame
game\GuessGame.java:54: error: cannot find symbol
System.out.println("Player three got it right? " + p3isRight)
^
symbol: variable p3isRight
location: class GuessGame
6 errors

the error is:

GameLauncher.java:4: error: cannot find symbol
GuessGame game = new GuessGame();
^
symbol: class GuessGame
location: class GameLauncher
GameLauncher.java:4: error: cannot find symbol
GuessGame game = new GuessGame();
^
symbol: class GuessGame
location: class GameLauncher
2 errors