Help needed with application: "could not find the main class"

I am pretty new to java and am trying to figure out applications a bit now. The one im working on does run within my editor, but when i "test" it or try to run it from within a .jar file it returns a "could not find the main class" error.
I have a code similar to this:
public class user{
public static void main(String[] args){
new user();
public user{
Does this have to do with it? I've been trying to get this right for a couple of days now, I just wanna be able to run it (on either my pc or another) without starting the Editor.
Looking forward to receiving an answer..

It sounds like you are missing the Main-Class attribute in your manifest file. Create a file 'manifest.mf' with the following line 'Main-Class: user'
Then include that manifest in your jar:
'jar -cfm user.jar manifest.mf user.class'
Then run the jar: 'java -jar user.jar'
http://java.sun.com/docs/books/tutorial/jar/basics/mod.html

Similar Messages

Problem with message: Could not find the main class Program will exit

I don't get why this isn't working. Any help is appreciated.
//Code start
public class hello{
public hello(){
public static void main( String args[] ){
System.out.println("Hello");
//Code end
I compile it as so:
javac hello.javaIt compiles fine and I now have hello.class in my current directory, but when I type the following:
java helloI get this:
Exception in thread "main" java.lang.NoClassDefFoundError: hello
Caused by: java.lang.ClassNotFoundException: hello
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)
Could not find the main class: hello. Program will exit.

mring001 wrote:
That worked. Thank you very much!Good. You should read [_Setting the class path_|http://java.sun.com/javase/6/docs/technotes/tools/windows/classpath.html] that tells you more about what the classpath is and how to set it.

Can not start WebLogic in Eclipse. Error: "Could not find the main class."

I have installed Eclipse 2.0 and WebLogic Server 6.1. and the WebLogc plug in from GENUITEC (and jdk1.3.1_04, on Win2K Server). After I have done the configuration, the WebLogic start/stop buttons are integried into the Eclipse Toolbar, but when I click on the start button to start Weblogic, it pops up a dialog box "Java Virtual Machine Launcher" with message: "Could not find the main class. Program will exit!"
Starting WebLogc Server from the Start panel works fine.
Does any one have seen this before or have a suggestion what I should do?
Many many thanks in advance.
Huan

Weblogic must be started with a full JDK; otherwise
JSPs and dynamic EJB stubs could not be deployed. The
error message
indicates you are attempting to use a JRE. Configure
Eclipse JRE to point to a JDK. The product
documentation will help you with this process. It does not work for me. :-(
I have tried JDK 1.3.1 and 1.4.1: same result: I get a "Could not find the main class: Program will exit"
For free expert support please consider contacting
Genuitec at [email protected] If just want any
answer ask a newsgroup.
WayneI'll try the support at '[email protected]' :)
Michel
Michel Szybist
[email protected]
Fax: +33 (0)173729897
SMS: http://www.szybist.net/

Could not find the main class - Problem with Webservice-Access

Hello Everybody,
I'm having serious Problems with accessing a WebService (Tomcat-Axis) per executable jar-File.
I constructed a simple GUI with 3 Textboxes 1 Button and 1 Resultbox.
I use eclipse so it was no Problem to simple generate the Backgroundclient by Processing the .wsdl-File of the WS.
Now I do this:
Head_tServiceLocator serviceLocator = new Head_tServiceLocator();
Head_t service = serviceLocator.getRPCCall();
RPCCallSoapBindingStub Head_t = (RPCCallSoapBindingStub) service;and use the Webservice like an Object.
All this works very well.
Now the Problem:
Head_t service = serviceLocator.getRPCCall();this Line has to throw a ServiceException.
If i add a try-catch Block to Process the Message JAVA tells me after i exported to JAR (with Manifest-stuff and so on) and double Click on the JAR the following :
Could not find the main Class - Program will exit.
And if i add a throws Declaration to the Methodheader it tells me:
Fatal Exception Occured - Program will exit
But if i Comment out that Line at least the GUI is being displayed (so it DOES find the main-Class). But then of course the Webservice won't be accessed.
All the JARs needed (axis.jar, commons-discovery.jar and so on) are in the same Directory as the Webservice-Client.jar
Please Help me.
Greets,
Zap

I am not done any typing mistake while creating the jar file i already followed the suggestion that you have mentioned but still the same error .
This is my MANIFEST.MF file created under META-INF folder
Manifest-Version: 1.0
Class-Path: qtjambi-4.4.3_01.jar qtjambi-win32-msvc2005-4.4.3_01.jar
Created-By: 1.5.0 (Sun Microsystems Inc.)
Main-Class: Ui_MainWindow
When i extracted the app.jar following this i got
1. META-INF folder inside that MAINFEST.MF file the contents i have already placed above
2. qtjambi-4.4.3_01.jar
3. qtjambi-win32-msvc2005-4.4.3_01.jar
4. Ui_MainWindow.class
Please tell me whats wrong in that i can also give you the app.jar file please let me know the email id ..

Could not find the main class: examples/Fibo. Program will exit. HELP!!!!!

I am trying to write a program that prints out the first 10 numbers of the fibonacci sequence. Unfortunately I am unsuccessful so far and getting nothing but errors. I am using jasmin and I have no idea what I am doing as this is my first time ever dealing with this language. I am not 100% sure but I am under the assumption is assembly but I only have luck doing a search by Java Virtual Machine. Can anybody help me with the following error. Any help will be much appreciated. Thanks in advance!!!
C:\Users\Chris\Desktop\jasmin\jasmin>java -cp . examples/Fibo
Exception in thread "main" java.lang.VerifyError: (class: examples/Fibo, method:
*main signature: ([Ljava/lang/String;)V) Expecting to find object/array on stack*
*Could not find the main class: examples/Fibo. Program will exit.*
Here is my written program
.class public examples/Fibo
.super java/lang/Object
; standard initializer
.method public <init>()V
aload_0
invokenonvirtual java/lang/Object/<init>()V
return
.end method
.method public static main([Ljava/lang/String;)V
    .limit locals 5
     .limit stack 10
    getstatic java/lang/System/out Ljava/io/PrintStream;
     astore_1
     bipush 10
     istore_2
     iconst_0
     dup
     ;invokevirtual java/io/PrintStream/println(I)V;
     ;invokestatic java/lang/String/valueOf(C)Ljava/lang/String;
     invokevirtual java/io/PrintStream/println(Ljava/lang/String;)V
     istore_3
     bipush 1
     istore 4
     L0:
     iload 3
     dup
     iload 4
     dup
     ;invokestatic java/lang/String/valueOf(C)Ljava/lang/String;
     invokevirtual java/io/PrintStream/println(Ljava/lang/String;)V
     iadd
     iload 4
     istore 3
     istore 4
     iload_2
     ifeq L1
     iinc 2 -1
     goto L0
     L1:
     return
.end method
OK guys I give up...I redid the program and its working better now.
*Note to moderators....if you please, you may delete this. Thanks!!!!!*
Edited by: chris52204 on Apr 12, 2009 3:21 PM

cojogrizli wrote:
The structure of my project in Eclipse is src/project/files.java and in jar file is src/files.java bin/class.java Dati/ and META-INF/.That's wrong. You don't need the .java files in the jar (but you can have them, if you want, they are just not used by Java).
And each .class file must be in a directory that reflects its package. So in your example ProjectGUI.class must be in the directory projectRFID/ inside the .jar file.

Could not find the main class (with every jar)

This isn't a developer question. I get the error Could not find the main class with every jar I try to open (for example the jar downloaded from https://gjar.dev.java.net/ gives the same problems - and I don't think there is something wrong with that JAR). It isn't a problem with the jar or MANIFEST because the same jar works fine on my laptop. So there is something wrong with my JRE installation, but what?
I tried to remove and reinstall the JRE 6 Update 18 but that didn't work. When I run the JAR with command line java -jar "file.jar" it works fine, but if I dubbelclick on it I get the error message (and it's irritating me).
I'm a bit desperate so I hope that someone here can help me ;)
Thanks in advanced

hai T.B.M ... Sorry to post here... I know that i posted my question in wrong thread..but i dont have another solution to contact with you.. I had seen your answers which are really excellent and helped to do my project..
Now i am having very less time to complete my project and i am very new to JMF.. I am not getting output in JMF video capture ..please check the code and guide me where i gone wrong.......please pardon me once again to post here.. Heres my code
import javax.media.*;
import java.awt.*;
import javax.swing.*;
import java.util.*;
import java.awt.event.*;
import javax.media.protocol.*;
import java.io.*;
import javax.media.control.StreamWriterControl;
public class webcam implements ActionListener,ControllerListener
boolean eomReached = false;
boolean realized = false;
JFrame f;
BorderLayout bd1;
CaptureDeviceInfo device;
MediaLocator m1;
Player player;
Component videoScreen;
JButton b1,b2;
Processor processor;
DataSource ds=null;
DataSink fileWriter=null;
JLabel status=new JLabel("");
public webcam()
try
JFrame f=new JFrame();
JPanel p =new JPanel();
JPanel p1=new JPanel();
device=CaptureDeviceManager.getDevice("vfw:Microsoft WDM Image Capture (Win32):0");
m1=device.getLocator();
System.out.println("1");
processor.configure();
processor = Manager.createProcessor(m1);
processor.setContentDescriptor(new
FileTypeDescriptor(FileTypeDescriptor.MSVIDEO));
ds=processor.getDataOutput();
player.addControllerListener(this);
MediaLocator dest = new MediaLocator("file://foo.avi");
fileWriter = Manager.createDataSink(ds, dest);
fileWriter.open();
ds.connect();
ds.start();
player=Manager.createPlayer(m1);
player.addControllerListener(this);
blockingRealize();
videoScreen=player.getVisualComponent();
b1=new JButton("START");
b2=new JButton("STOP");
bd1=new BorderLayout();
p.setLayout(bd1);
p1.add(b1);
p1.add(b2);
p.add("South",p1);
p.add("East",videoScreen);
f.getContentPane().add(p);
f.setVisible(true);
f.setSize(500,500);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
b1.addActionListener(this);
b2.addActionListener(this);
catch(Exception e){}
public void actionPerformed(ActionEvent e)
if(e.getSource()==b1)
try{
processor.start();
player.start();
fileWriter.start();
catch(Exception e1){}
if(e.getSource()==b2)
try{
player.stop();
processor.stop();
processor.close();
fileWriter.close();
catch(Exception e2){}
public static void main(String args[])
webcam obj=new webcam();
public synchronized void blockingRealize() {
player.realize();
while (!realized) {
try {
wait();
} catch (java.lang.InterruptedException e) {
status.setText("Interrupted while waiting on realize...exiting.");
System.exit(1);
public synchronized void controllerUpdate (ControllerEvent event) {
System.out.println("myPlayer generated "+event.toString());
if (event instanceof RealizeCompleteEvent) {
realized = true;
notify();
} else if (event instanceof EndOfMediaEvent) {
eomReached = true;
}

Could not find the main class error with executable jar

Hello,
I have troubles creating an executable jar file and I ran out of ideas how to solve it so I would appreciate some help.
I have created a jar file with the export function in eclipse
the Manifest.MF file contains:
Manifest-Version: 1.0
Main-Class: view.AppTennisViewI tried starting the file with a batch file which contains following code:
@echo off
javaw -classpath c:\TennisHSQLDB_GC2\tennisApp.jar
@start javaw -jar tennisApp.jar
exitthe batch file and the jar are both located in c:\TennisHSQLDB_GC2.
When i try command line I get the same result.
I also tried alternate statements such as SET CLASSPATH iso javaw -classpath and including the classpath in the manifest file but no luck. It keeps given me the error: could not find the main class. program will exit
Anyone any suggestions for my problem?

nevermind, found it.
classpath in manifest was incorrect

Help Me Urgent...Error: "Could not find the main class. Program will exit."

Am using Eclipse 3.3.2
I have a project called: SWDS
Initially i have JDK1.6 installed in my system. At this time the project is running succesfully.
But when i removed(uninstalled and environment path also removed) JDK 1.6 and installed JDK 1.5 and path also given.
No changes are made in the project code.
When I Run the project SWDS then showing an alert "*Could not find the main class. Program will exit*" and then getting error messages like:
{color:#ff0000}java.lang.UnsupportedClassVersionError: Bad version number in .class file
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.access$100(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)
Exception in thread "main"{color}
Pleez help me how to rectify this error.

The manifest file is missing from the project.
I searched the net and read about the manifest file and I saw that it is supposed to be located in META-INF/MANIFEST.MF. I suppose that means project_root/META-INF/MANIFEST.MF, right ?
I am asking this because I haven't got that much experience in Java and this is the first time I hear about a manifest file.
Does anyone have any Ideea how I add a manifest file to a project with Eclipse SDK? I searched the menus and I didn't find anithing of such sort... o
Does Eclipse have support for editing manifest files at all?

Could not find the main class JRE 1.6 only with console program into Contro

Hi,
I want replace JRE1.5-11 with JRE 1.6.
Applet is running correctly with JRE 1.6.
But when i want launching Java program located into "Parameters/Control Panel"
I have following error message "Could not find the main class JRE 1.6 "
Regards
Philippe

i wouldn't report a nullpointer to sun unless you're fairly confident there's some sort of bug. if main() can't be found it sounds to me like a config issue. if nullpointer, sounds like a code issue. post the code if you want, but i don't think sun will help you debug this.

Could not find the main class: projectRFID.ProjectGUI. Program will exit.

Hello,
I'm quite new in Java. I have an application with GUI. When I'm using Eclipse version 3.4.0 to run the application, all it is working perfect.
But after I generate the jar from Eclipse, using the manifest file option from there and added the ProjectGUI to it, where is the main class, and try to run from the command line I receive the next error:
root@slax:~/workspace# java -jar rfid.jar
Exception in thread "main" java.lang.NoClassDefFoundError: projectRFID/ProjectGUI
Caused by: java.lang.ClassNotFoundException: projectRFID.ProjectGUI
at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
Could not find the main class: projectRFID.ProjectGUI. Program will exit.
root@slax:~/workspace#
I run this application on a SLAX system with jdk6 update 7.
I tried to generate the jar file even from the command line using the manifest file option but I still receive the same error.
I hope somebody can help me!
Thank you!

cojogrizli wrote:
The structure of my project in Eclipse is src/project/files.java and in jar file is src/files.java bin/class.java Dati/ and META-INF/.That's wrong. You don't need the .java files in the jar (but you can have them, if you want, they are just not used by Java).
And each .class file must be in a directory that reflects its package. So in your example ProjectGUI.class must be in the directory projectRFID/ inside the .jar file.

Could not find the main class: oracle.ide.boot.Launcher. Program will exit

Hi,
I have installed Oracle11g_win64_11gR1, Database and Client.
The issue is unable to invoke "sqldeveloper", getting the following error message. Could you please help ?
FYI. I have already downloaded and installed installed JRE and JDK.
ie. C:\Program Files (x86)\Java\jre6\ and C:\Program Files\Java\jdk1.6.0_24, still did not work.
C:\Users\oracle>java -version
java version "1.6.0_24"
Java(TM) SE Runtime Environment (build 1.6.0_24-b07)
Java HotSpot(TM) 64-Bit Server VM (build 19.1-b02, mixed mode)
Let me know, if you need more information. Here is the error message.
Error Message
=========
(1) if I invoke sqldeveloper, directly from the location " C:\app\oracle\product\11.1.0\db_1\sqldeveloper\sqldeveloper\bin " using explorer, I do get error message
"Unable to find a java Virtual Machine.
To point to a location of java Virtual machine please refer to the Oracle9i JDeveloper Install Guide ( jdev/install.html)"
(2) if I invoke sqldeveloper, directly from the locationC:\app\oracle\product\11.1.0\client_1\sqldeveloper, it prompts me to enter "full path for java.exe".
When I enter full path and continue, still it continue to prompt and ask the same input.
(3) if I invoke sqldeveloper from from command prompt using the batch file "sqldeveloper.bat"
C:\Users\oracle>C:\app\oracle\product\11.1.0\client_1\sqldeveloper\sqldeveloper\
bin\sqldeveloper.bat
C:\Users\oracle>java -Xmx512M -Xverify:none -XX:JavaPriority10_To_OSPriority=10
-XX:JavaPriority9_To_OSPriority=9 -Doracle.ide.util.AddinPolicyUtils.OVERRIDE_F
LAG=true -Dsun.java2d.ddoffscreen=false -Dwindows.shell.font.languages= -Dide.co
nf="sqldeveloper.conf" -Dide.home.dir.name=.sqldeveloper -classpath ..\..\ide\l
ib\ide-boot.jar;..\..\jdev\lib\xmleditor.jar;..\..\ide\lib\oicons.jar;..\..\..\j
dbc\lib\ojdbc5.jar;..\..\jlib\jewt4.jar;..\..\jlib\share.jar;..\..\sqldeveloper\
lib\jle2.jar oracle.ide.boot.Launcher
Exception in thread "main" java.lang.NoClassDefFoundError: oracle/ide/boot/Launc
her
Caused by: java.lang.ClassNotFoundException: oracle.ide.boot.Launcher
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
Could not find the main class: oracle.ide.boot.Launcher. Program will exit.
OS
==============
MS Windows 7 Home Premium
sqldeveloper.conf
===================
SetSkipJ2SDKCheck true
IncludeConfFile ../../jdev/bin/ide.conf
AddVMOption -Dapple.laf.useScreenMenuBar=true
AddVMOption -Dcom.apple.mrj.application.apple.menu.about.name="SQL_Developer"
AddVMOption -Dcom.apple.mrj.application.growbox.intrudes=false
AddVMOption -Dcom.apple.macos.smallTabs=true
AddVMOption -Doracle.ide.util.AddinPolicyUtils.OVERRIDE_FLAG=true
AddJavaLibFile ../../jdev/lib/xmleditor.jar
AddJavaLibFile ../../ide/lib/oicons.jar
AddJavaLibFile ../../jlib/jewt4.jar
AddJavaLibFile ../../jlib/share.jar
AddJavaLibFile ../ide/jlib/xmlef.jar
AddJavaLibFile ../../sqldeveloper/lib/jle2.jar
AddJavaLibFile ../../sqldeveloper/lib/oracle.dbtools.logging.jar
AddVMOption -Dsun.java2d.ddoffscreen=false
AddVMOption -Dwindows.shell.font.languages=
IncludeConfFile sqldeveloper-nondebug.conf
SetJavaHome C:\Program Files\Java\jdk1.6.0_24
Edited by: sivapara on Feb 16, 2011 1:08 PM

I was able to resolve this issue by performing following.
1. Go to the location where sqldeveloperW.exe is being executed from.
2. You will find a file sqldeveloper.conf in that location. Edit this file and change the value of IncludeConfFile to point to actual place. For me following were old and new values.
OLD (Wrong) : IncludeConfFile ../../jdev/bin/ide.conf
NEW (Correct) : IncludeConfFile ../../ide/bin/ide.conf
After making above change in the sqldeveloper.conf file. Save and close it. Restart SQLDeveloper. You will not get the error anymore.
Thanks
Ravi

Execute jar file: "could not find the main class" program will terminate

Hey,
I am new to Java. I have started to make a small java program which supposed to help me at my studies to lean the Dominic Memory System. I have used the latest version of Netbeans 5.5.1 to build my program in. I have two problems which I cannot figure out how to solve, please help me.
The first problem is that the java script I have made works when I compile it in Netbeans, but when I create a Jar file it does not work. I receive a pop up message in windows ?could not find the main class program will terminate? when I execute the jar file.
The second problem I have is that I need to compare the strings generated by the "numbers" and "TIP" and if the numbers is not identical the numbers in the ?Center? JPanel should be highlighted as red.
If anyone would like to clean up the code I would be pleased. I have copied quite a lot from anyone because of my one lack of knowledge.
* GoListener.java
* Created on 12. september 2007, 21:48
* To change this template, choose Tools | Template Manager
* and open the template in the editor.
package grandmaster;
import java.awt.event.*;
import javax.swing.*;
import java.util.Vector;
import java.util.StringTokenizer;
import java.awt.Color;
* @author Computer
public class GoListener implements ActionListener {
private JTextField viewer;
private JTextField TIP;
private JTextField freq;
private JTextField max_num;
private Vector numbers;
public GoListener(JTextField j,JTextField k, JTextField m, JTextField f, Vector n) {
freq = f;
max_num = m;
viewer = j;
numbers = n;
TIP = k;
public void actionPerformed(ActionEvent e){
int time = Integer.valueOf(max_num.getText());
int f = Integer.valueOf(freq.getText());
if (e.getActionCommand() == "GO") {
for (int i = 0; i< time;++i) {
int number=0;
number = (int)Math.floor(100*Math.random());
while(number>51){
number = (int)Math.floor(100*Math.random());
if(number<=9){
viewer.setText(" "+"0" + String.valueOf(number) + " ");
} else{
viewer.setText(" " + String.valueOf(number) + " ");
viewer.paintImmediately(viewer.getBounds());
numbers.add(number);
try {
Thread.sleep(f*1000);
} catch (Exception exp) {
viewer.setText(" XX ");
viewer.paintImmediately(viewer.getBounds());
if (e.getActionCommand() == "VIEW") {
try {
//int numb = Integer.valueOf( TIP.getText() ).intValue();
StringTokenizer tokenizer = new StringTokenizer(TIP.getText(), " ");
String[] split = null;
int tokenCount = tokenizer.countTokens();
if (tokenCount > 0) {
split = new String[tokenCount];
for (int current = 0; current < tokenCount; current++) {
split[current] = tokenizer.nextToken();
viewer.setText(" " + String.valueOf(numbers) + " ");
// k=numbers(1);
/*while(c<i){
String.valueOf(k).equals(split[1]);
c++;
TIP.setText(" " + split[2] + " ");
} catch (Exception exp) {
try {
//string testit = numb.toString();
//String str = "" + numb;
//viewer.setText(str);
//viewer.setText(numbers.toString());
numbers.clear();
} catch (Exception exp) {
* Main.java
* Created on 12. september 2007, 21:07
* To change this template, choose Tools | Template Manager
* and open the template in the editor.
package grandmaster;
import java.util.Vector;
import javax.swing.*;
import java.awt.event.*;
import javax.swing.JButton;
import java.awt.*;
import grandmaster.GoListener;
* @author Computer
public class Main extends JFrame {
private JTextField viewer;
public JTextField TIP;
// private TextInputPanel TIP;
private Vector numbers;
/** Creates a new instance of Main */
public Main() {
numbers = new Vector();
JPanel p = new JPanel(new GridLayout(0,4));
JButton go = new JButton();
JButton view_num = new JButton();
go.setText("Go!");
go.setVisible(true);
go.setActionCommand("GO");
view_num.setText("VIEW");
view_num.setVisible(true);
view_num.setActionCommand("VIEW");
JTextField max_num = new JTextField();
max_num.setText("5");
JTextField freq = new JTextField();
freq.setText("1");
viewer = new JTextField();
viewer.setText("XX");
TIP = new JTextField("");
p.add(go);
p.add(max_num);
p.add(freq);
p.add(view_num);
getContentPane().add(p,BorderLayout.NORTH);
getContentPane().add(viewer,BorderLayout.CENTER);
getContentPane().add(TIP,BorderLayout.SOUTH);
setSize(200,200);
GoListener g = new GoListener(viewer,TIP,max_num, freq, numbers);
go.addActionListener(g);
view_num.addActionListener(g);
* @param args the command line arguments
public static void main(String[] args) {
// TODO code application logic here
Main window = new Main();
window.setVisible(true);
}

NetBeans questions should be posted to the NB site. It has mailing lists and associated forums.
This tutorial from the NB site addresses running programs outside of NB
http://www.netbeans.org/kb/articles/javase-deploy.html
When you compare objects, use ".equals()" and reserve == for comparing values.

Executable JAR file: Could not find the main class.

Hello,
I have a problem with making an executable JAR file.
I have written a JAVA program that consists of five different classes of which User.java is the main class and I have saved a text document with Main-Class: User and a blank line after that.
If I try:
jar cmf MainClass.txt User.jar User.class Beheerder.class Operator.class Manager.class MaakVisueelSchema.class
it makes a executable jar file which actually works! :)
But when the Operator class trys to open the MaakVisueelSchema class the screen stays blank.
I can run MaakVisueelSchema with java MaakVisueelSchema.
So I tried to make an executable JAR that consists only of MaakVisueelSchema, the same way as I did for User:
Main-Class: MaakVisueelSchema
jar cmf MainClass.txt MaakVisueelSchema.jar MaakVisueelSchema.class
Then I get the error message:
Could not find the main class. Program will exit.
from the Java Virtual Machine Launcher.
The big difference between MaakVisueelSchema and the other classes is that MaakVisueelSchema contains a PaintComponent method and an ComponentListener. Is it possible that one of those creates the error?
Can anyone help me with this problem?
Thanks in advance!
Bye!

Yes,
I tried:
jar xvf MaakVisueelSchema.jar
and it returns:
META-INF/
META-INF/MANIFEST.MF
MaakVisueelSchema.classN/G. You need to manually create a manifest file in a text editor, have it point to your main class, and enter it in your jar command as an argument.

Could not find the main class : HelloWorldApp program will exit

please help me
i downloaded and installed jdk-6u13-windows-i586-p(1) from sun.java.com
in my computer --> Advanced --> environment variables --> i had set
user variable :
variable value
java_home C:\Program Files\Java\jdk1.6.0_13\bin
System variable:
path : C:\Program Files\Java\jdk1.6.0_13\bin
after that i wrote a program
* The HelloWorldApp class implements an application that
* simply prints "Hello World!" to standard output.
class HelloWorldApp {
public static void main(String[] args) {
System.out.println("Hello World!"); // Display the string.
i saved in c:\ mywork
i compiled it with
javac HelloWorldApp.java and then
java HelloWorldApp
output / result also came
but iam unable to create jar file . when it is created it is showing
could not find the main class : HelloWorldApp program will exit
i created jar file by following way
i created
manifest.txt
Min-Class : HelloWorldApp and then
start -->run--> cmd-->
c:\mywork> jar cfm test.jar manifest.txt HelloWorldApp.class
c:\ java -jar test.jar
but it displays a message
" could not find the main class : HelloWorldApp program will exit "
please please please help me please 1000's of please help me

Peter__Lawrey wrote:
You have to specify the manifest with a special option (I think its was -M)
Otherwise the jar will create one (even if you provide it)No, the text file passed as a parameter will be incorporated in the manifest file generated by the JAR tool.
@OP: This will work:
JarTest.java
public class JarTest {
public static void main(String[] args) {
System.out.println("JarTest works!");
}manifest.txt
Main-Class: JarTest+(note there is an extra new line in the manifest.txt!)+
Now execute these commands:
javac JarTest.java
jar cfm MyJar.jar manifest.txt JarTest.class
java -jar MyJar.jar And on my machine, the string "JarTest works!" is displayed on the screen.
And if you look in the MANIFEST.MF file inside your jar file (you can use almost any zip-utility for this), you will see the following:
Manifest-Version: 1.0
Created-By: 1.6.0_0 (Sun Microsystems Inc.)
Main-Class: JarTestOr something similar.

Error msg Could not find the main class.Program will exit. in jar execution

Hello,
I have created a jar so that I can used it in the webapp.
but when I click on it it says "Could not find the main class.Program will exit."
I searched a lot in the net and found that it has to do with the manifest file.
I even updated the manifest file using the command "jar umf main.txt filefolderupload.jar" with the class name mention along with the package heirarchy.
(pakage heirarchy in /,\ and .)
I am using JDK 1.5 . and have Updated JRE 1.6.
Also tried with extending the class with JApplet, but in vain.
Kindly help me in the above mention issue.
tia,
Sarwa

This post hints at a number of misunderstandings on your part, and raises a couple of important questions.
Note that this 'simple question' has a complicated answer. Given the complexity of it, it might pay to add Dukes to it, ..a lot of Dukes.
The important questions are.
1) Does this file/directory uploader need to provide the end-user with a file dialog in which they can choose a local directory to upload, or will a multi-file chooser do?
2) Does this uploader need to upload to foreign sites, or does it upload back to its own server?
Looking at this table I prepared to describe the [uploader/local file access|http://pscode.org/test/uploader/fileuploader.html] possibilities, if the answers to the questions are 'multi-file chooser will do' and 'home site only', the best option is a sandboxed app. launched using webstart (JNLP) - option 5. If either of those questions go the other way, option 6 (digitally signed with extended permissions) is needed.

Help needed with application: "could not find the main class"

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