Jar file error: could not find main class. program will exit

I have created a jar file using following command
jar cfm MyProj.jar Manifest.txt richa\*.class
and I have included main class header in the Manifest.txt. The executable jar file is created but when I double click on it, it prompts an error Could not find the main class. program will exit.
Please help. Its urgent..
Thanks in advance

This simply state that jvm was unable to fine Main Class file.
I hope you have configured manifest file including your main file information and class path used by the project with proper package hierarchy,
as described in article
[https://java.sun.com/docs/books/tutorial/deployment/jar|https://java.sun.com/docs/books/tutorial/deployment/jar]
Edited by: Deepesh on Jul 13, 2008 4:58 AM

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Could not find main class program will exit error while installing Oracle Client 32 bit on windows 7 32 bit OS?

Hi Experts,
When I am installing Oracle client 32 bit software on Windows 7 32 bit I am getting error as "could not find main class program will exit"
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[Oracle]
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Duplicates of the other two times you asked this question:
https://forums.oracle.com/thread/2559093
https://forums.oracle.com/thread/2558027
(and this time, your question does not appear to have anything to do with this particular forum space, either)
Duplicate is locked.
Do not EVER multi--post. That is extremely bad forum etiquette.

Uh oh... ERROR "Could not find main class" BmpImageReader.class

Ooopss.. i broke it... was working , but yep.. i broke it
Class File Editor
Source not found
The source attachment does not contain the source for the file BMPImageReader.class
You can change the source attachment by clicking Change Attached Source below:
public class com.sun.imageio.plugins.bmp.BMPImageReader extends javax.imageio.ImageReader implements com.sun.imageio.plugins.bmp.BMPConstants
Long list of constants follow.. blah blah
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Ah what the.. its working again.... odd.. very odd.. I don't know how to delete this thread , but go ahead you all mighty powerful moderators..
Edit: Yeah I had a main function.. maybe I accidentaly deleted or added a bracket or something I don't know.. very strange..
Message was edited by:
Kurisu

Jar file could not find main class.. I cant see why?

I have read loads of tutorials on this and it should be very straight forward but i STILL cant make a working jar file of my program.. please see if you can see anything wrong with what im doing..
my program is one .java file that compiles perfectly, and is runnable both through eclipse and by using the command prompt.. i made a jar file using both eclipse and the command prompt, and neither worked.. every time i run it by double clicking it i get the error "could not find main class, program will exit". here is the contents of my jar:
CorePackage\IPEmailer.class
CorePackage\IPEmailer$1.class
CorePackage\IPEmailer$SMTPAuthenticator.class
META-INF\MANIFEST.MF
the MANIFEST.MF file contains:
Manifest-Version: 1.0
Class-path: .
Created-By: 1.6.0_02 (Sun Microsystems Inc.)
Main-Class: CorePackage.IPEmailer
(yes there is a blank line at the end)
the class mentioned in 'Main-Class' has a main method that looks like this:
public static void main(String[] args) {
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    new IPEmailer();
}the program uses 2 external jar files:
activation.jar
mail.jar
and reads a file called:
ipemailer.ini
and writes a file called:
ip.txt
the program has no GUI and is intended to run 'silently' in the background
please help me understand what is wrong with this

package CorePackage;
import javax.mail.*;
import javax.mail.Authenticator;
import javax.mail.PasswordAuthentication;
import javax.mail.internet.*;
import java.util.*;
import java.io.*;
import java.net.*;
public class IPEmailer implements Runnable{
      * @param args
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     String body;
     String server;
     String user;
     String pass;
     String from;
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     String currentIP;
     String ipFromFile;
     boolean webFailed;
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     long oldInterval;
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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.

Error:-could not find the main class programe will exit(Java virtual mach)

Hi,
i changed the mainfest file for an executive jar file(judge.jar) using the command on dos :-"jar cvfm judge.jar c:\judge\MAINFEST.MF -C judge/ ." , but when i run this jar file again after making changes in mainfest file it is not working. an error encounter like "could not find the main class programe will exit how to solve"(Java virtual machine launcher).please suggest me how to solve this error.
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Ashwani Gupta

Hi,
mainfest file has a entry like "main -class: judge.repository.corpus"
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Ashwani

JAR: - Could not find main class

I'm sorry, I know this issue has been posted before but I am a bit confused with my situation.
After making a jar on my computer, I run it, and the program loads and runs perfectly.
However, when I try the jar on someone else's computer, it doesn't work, and gives the "could not find main class" message. The other computer has JRE but not JDK, so I don't know if that makes a difference.
Anyways, my main class file is located in a package called hw2, and the whole project is located in a folder called HW2. So my class file is located in something like C:\School\HW2\hw2\Main.class.
My Manifest.txt file is located in the \School\HW2 directory and has the following with a new line at the end:
Main-Class: hw2.Main
At the command prompt, I go to my C:\School\HW2 directory and I type the following to create the jar:
jar cvmf Manifest.txt test.jar hw2\*.class
My jar file has the following contents:
META-INF/
META-INF/MANIFEST.MF
hw2/Bank.class
hw2/GUIInterface.class
hw2/Main.class
Did I write the manifest.txt file correctly? Am I in the right directory when creating the jar file? Am I executing the jar command wrong? How come it works on my computer but not on someone else's?

Are you certain you're executing the jar in the same way on both machines?
For example, are you sure you're not executing the unjarred class files when you run on your local machine?

Can't find main class - program will end

Dear forum readers,
Recently upgraded from Win2k pro to XP pro .. installation ran to conclusion w/ no fatal errors BUT upon booting new system I now receive an error message "Java Virtual Machine Launcher can't find main class, program will end" .. I am not aware that this error is causing any problems BUT it is annoying and I'd like to be able to fix the problem so I don't have to close the error message at each startup .. please help!
Thanks in advance, Larry

Try this
java -XbootClasspath/a -jar <<Prog name>>
I think you are trying in windows XP.
Also you need to modify if there are any other jars to be reference. For eg if a.jar is also required for this try as below
java -XbootClasspath/a:a.jar -jar <<Prog name>>

Could not find Main Class while executing JAR

Hello all,
I am having a simple Jar file that contains one java class that merely displays a window. I am using NetBeans IDE to create the JAR file. When i execute this JAR file by double clicking on the file, it works fine on the machine. However, if i try to execute this same file on any other windows computer, it gives an error "Could not find the main class. Program will exit."
In other words, the JAR file is only working on the computer that has NetBeans and JDK installed on. Not on any other machine. Although the other machines have the JAVA Virtual Machine installed.
I would appreciated any help on this topic.

I had the same problem (i.e. Message-Box with "Could not find the main class. Program will exit.")
After insuring that the manifest contained a Main-Class: argument and that the argument pointed to the right class, I started the jar via java -jar myjar.jar and read the stacktrace, which is much better than the popup-window.
In my case the error was, that the Main-Class could not be loaded due to another referenced class, which was not on the classpath. (i.e. it was not in the same jar-File and the manifest didn't include a Class-Path: argument.)
After adding the correct Class-Path: argument in the manifest, the problem went away.
I now have the following setup:
myjar.jar and somethirdparty.jar in the same directory.
myjar.jar contains a manifest which includes the lines
Class-Path: somethirdparty.jar
Main-Class: my.package.and.MainClassafter the normal Manifest-header.

Could not find main class. Program will now exit. *SIGH*.....

At first I thought it was just my own programs that I created with netbeans that had this problem; however, even the demo programs under the sdk folder give me this problem when i try to run them. Virtual Machine Loader will just come up with pop up saying "Could not find the main class. Program will not exit"
I am a fairly competent programmer, not new to java. But I am new to guis in java, and using netbeans to create them. The program I am creating gives me this error with javaw and with java it will tell me NoClassDef for grouplayout. I checked the manifest file it looks alright:
Manifest-Version: 1.0
Ant-Version: Apache Ant 1.7.0
Created-By: 10.0-b19 (Sun Microsystems Inc.)
Main-Class: desktopapplication2.DesktopApplication2
Class-Path: lib/appframework-1.0.3.jar lib/swing-worker-1.1.jar lib/swing-layout-1.0.1.jar lib/ant-swing.jar lib/SwingSet2.jar lib/swing-layout-1.0.3.jar
X-COMMENT: Main-Class will be added automatically by build
}(brackets not included)
I am sort of lost.... Do I need to install ant separately?
I feel like there may be some classpath issues?
I have java 1.6 update 4 and netbeans 6.0
I am completely lost I have been working on fixing this for the past 2 or 3 days now, and reading up all the information.
Note: This is just a standard desktop application.
Also I just thought of something. If I have install the development kit do I also need to install the framework or whatever for 6.0 separately? Meaning installing the latest version of jvm. Sorry if this isn't clear i forgot what it is called.
Sorry if this sounds like a beginner question or something, but I am going crazy. If i am having this much trouble running my own program i really hope distributing files won't be this much of a nightmare....

Please become familar with resources at the NetBeans site. There are tutorials and FAQs that cover usage of NB, and how to do things like you're asking.
See my reply in this thread for more information
http://forum.java.sun.com/thread.jspa?threadID=5270931&tstart=0

Another "could not find main class" thread

Hello everybody
I know there's tons of threads on this subject but none of them seem to be quite like mine.
I'm trying to deploy an application that I developped with Jbuilder 2006 Enterprise (trial version). It automatically created the "ServerApp.jar" file and the manifest but when I try to run it I get the famous message: "Could not find the main class. Program will exit." My main class is "Application" and it's in a package called "serverapp".
here's a copy of my manifest:
Manifest-Version: 1.0
Main-Class: serverapp.Application
it has two extra lines at the end.
I read on the other threads that I also needed a .bat file (don't know quite why) so I created one. It looks like this:
@ECHO ON
Set Path = C:\Program Files\Java\jre1.5.0_04\bin
cd C:\Documents and Settings\Naby\My Documents\Travail\Synapco\BlackeBerry\ServerApp
javaw -jar ServerApp.jar
EXIT
One last thing: when I run the .jar file from the command line using the syntax
java -jar serverapp.jar
I get this more detailled error message:
C:\Documents and Settings\Naby\My Documents\Travail\Synapco\BlackeBerry\ServerAp
p>java -jar serverapp.jar
Exception in thread "main" java.lang.SecurityException: no manifiest section for
signature file entry javax/mail/internet/AsciiOutputStream.class
at sun.security.util.SignatureFileVerifier.verifySection(SignatureFileVe
rifier.java:377)
at sun.security.util.SignatureFileVerifier.processImpl(SignatureFileVeri
fier.java:231)
at sun.security.util.SignatureFileVerifier.process(SignatureFileVerifier
.java:176)
at java.util.jar.JarVerifier.processEntry(JarVerifier.java:233)
at java.util.jar.JarVerifier.update(JarVerifier.java:188)
at java.util.jar.JarFile.initializeVerifier(JarFile.java:318)
at java.util.jar.JarFile.getInputStream(JarFile.java:383)
at sun.misc.URLClassPath$JarLoader$1.getInputStream(URLClassPath.java:62
0)
at sun.misc.Resource.cachedInputStream(Resource.java:58)
at sun.misc.Resource.getByteBuffer(Resource.java:113)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:249)
at java.net.URLClassLoader.access$100(URLClassLoader.java:56)
at java.net.URLClassLoader$1.run(URLClassLoader.java:195)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:268)
at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)
I don't know what is going on here.
Any help would be really appreciated
Thanks.

Thanks for the reply martin
what jar file are you refering to? I only have one jar file wich is "serverapp.jar" and that's the one I want to run.

Could not find main class!

I tried some code I got from a book I recently bought it compiled ok but when I tried to run it in JPadPro I got the Java Virtual Machine Launcher warning saying 'Could not find the main class. Program will exit!' As far as I can see there is a main method so I am not to sure what the actual problem is. I pasted the code below hopefully someone can help, Dave.
* Copyright (c) 2000 David Flanagan. All rights reserved.
* This code is from the book Java Examples in a Nutshell, 2nd Edition.
* It is provided AS-IS, WITHOUT ANY WARRANTY either expressed or implied.
* You may study, use, and modify it for any non-commercial purpose.
* You may distribute it non-commercially as long as you retain this notice.
* For a commercial use license, or to purchase the book (recommended),
* visit http://www.davidflanagan.com/javaexamples2.
package com.davidflanagan.examples.datatransfer;
import java.awt.*;
import java.awt.event.*;
import java.awt.datatransfer.*;
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* to an application.
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     try {
         if (t.isDataFlavorSupported(DataFlavor.stringFlavor)) {
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Oh, no wonder I have such low "reading for comprehension" scores - that was a "package" statement, not an "import".
Thing is, your class would compile with this package statement there - but, the interpreter wouldn't be able to find it, 'cause the compiled class would be in a package called com.davidflanagan.examples.datatransfer accoding to the class file, but your interpreter would be looking for the class in the default package (if that makes sense). If executed on the command line you would likely see something like:
Exception in thread "main" java.lang.NoClassDefFoundError: SimpleCutAndPaste (wrong name: com/davidflanagan/examples/datatransfer/SimpleCutAndPaste)
[pre]
Lee

Java Virtual Machine. Could not find main class

I am trying to install Oracle Data Access Components ODAC 11g 11.1.0.6.21
on windows 2008. I get the dreaded could not find the main class. Program will ext.
I have seen all the post, tried installing every conceivable Java version, removed all java version.
Nothing works. Does anyone have THE solution for this on-going error?
Thanks

I fixed my problem by installed Oracle 11g ODAC and Oracle Developer Tools for Visual Studio 11.1.0.7.20

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.

Could not find Main Class while running JAR outside /dist directory

Hello
I can make jar on netbeans by clicking Shift+F11. But the problem occurs when I copy paste my jar file out of /dist directory. It only works at /dist directory. I think my way making jar is incorrect. Anyone knows a way to make runnable jar by NetBeans instead of Shift + F11

Crossposted here:
[http://forums.sun.com/thread.jspa?threadID=5369074]
Don't do that.

Jar file error: could not find main class. program will exit

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