CAN NOT FIND MAIN CLASS

Why after i have unzipped and edited the classes in the jar file and zipped them together again, it gives me the message "CAN NOT FIND MAIN CLASS"?
This is after i have edited any class in the .jar zip.I did not edit the Manifest text file,can someone who has experienced this problem show me how to overcome it.
Thank you.

i think you have to read the "java tutorial on Jar files".
i guess after you have exracted the .jar file then you've edited the ".class"(i dont know how you did it) but i think you mean ".java" you should create another .jar file to be able to reflect the changes you have made, then set the main-class attribute of the newly created .jar file.

Similar Messages

Can not find Main Class - Can't Run Application

I have at this for a while and it is drivng me crazy... I have an application that I want execute in a bat file. I have checked the runtime environment by executing java and javaw, both which give option on error messages. I have set the classpath to point too the class subdirectory. Here it is.., Every time I execute the bath file or execute the javaw command, I get the "Can not find main class" message.
I am using XP ...
Help please...
Thanks for all your help.

when you set the classpath I presume you mean that your running java or javaw as:
javaw.exe -cp %classpath%;.;c:\library\myfiles com.mycomp.myapp.MainClassIf your using a jar then you must specify the jar in the class path.
Don't presume it will find the jar. Other than that, you will have
to provide more details.

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) {
    // TODO Auto-generated method stub
    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
     String recipientsinput[]={""};
     String subject;
     String body;
     String server;
     String user;
     String pass;
     String from;
     String urlString = "http://www.whatismyip.org";
     String currentIP;
     String ipFromFile;
     boolean webFailed;
     long interval = 900000; //15 mins
     long oldInterval;
     Thread t = new Thread(this);
     public static void main(String[] args) {
          // TODO Auto-generated method stub
          new IPEmailer();
     public IPEmailer(){
                     ..........etccould the problem be that the class is a thread? i cant see why it would be, but ive never made a jar where the main class also 'implements runnable'

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 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"
I have tried installing latest Java software 7 also JDK 1.6.0_34 still I am getting the same problem below is my " oraparam.ini " details
[Oracle]
DISTRIBUTION=TRUE
SOURCE=../stage/products.xml
LICENSE_LOCATION=
BOOTSTRAP_COMPS="oracle.swd.oui:11.1.0.6.0,oracle.swd.oui.core:11.1.0.6.0,oracle.jdk:1.5.0.1.1"
JRE_SCRATCH_LOC=jdk/jre
JRE_MEMORY_OPTIONS=" -mx96m"
DEFAULT_HOME_LOCATION=product\11.1.0\client
DEFAULT_HOME_NAME=OraClient11g_home
NO_BROWSE=/net
NLS_ENABLED=TRUE
BOOTSTRAP=TRUE
EXT_JLIB=../stage/ext/jlib
OUI_VERSION=11.1.0.6.0
## JRE_VERSION is only for Windows. This is to copy accessbridge dlls
JRE_VERSION=1.4.2
ACCESS_DIR=../install/access
#SHOW_HOSTNAME=ALWAYS_SHOW shows the hostname panel always
#SHOW_HOSTNAME=NEVER_SHOW does not the hostname panel
#SHOW_HOSTNAME=CONDITION_SHOW shows the hostname panel on condition
SHOW_HOSTNAME=NEVER_SHOW
#THIN_JDBC_FILENAME is optional and defaults to classes12.jar
#The value specified for this should be packaged with OUI, and should
#be relative to <OUI expanded stagedir>/jlib/
THIN_JDBC_FILENAME=classes12.jar
#RUN_OUICA specifies the batch script name that needs to be run
#The script is ouica.bat for win32, and ouica.sh for solaris.
#If the value is not specified, then the OUICA script is not run
RUN_OUICA=ouica.bat
CLUSTERWARE={"oracle.crs","10.1.0.2.0"}
SILENT_VARIABLE_VALIDATION=TRUE
[Generic Prereqs]
MIN_DISPLAY_COLORS=256
[IMAGES]
FILE1=images/billboards.gif
LICENSE_LOCATION=license.txt

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.

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?

Installing 10g on Windows XP machine JVM launcher "Can't find main class"

I am trying to install 10g Release 2 on a Windows XP machine. I downloaded the zip from the OTN. Unzipped the file. No problems. Tried to run the OUI, it opened up a shell and said to wait. The shell closed and a message frome the JVM Launcher displayed "Can't find main class. Program will exit." I have seen several people on this and other discussion boards having this problem, but have yet to get a solution. Please help.

What's the value of CLASSPATH environment variable? Possibly a non-oracle application has set this variable and the installer catches it. If there is such a variable, comment it out and try again.

Background callable object : can not find this class name

Hi All ,
I am following this tutorial link for creating background callable object
http://help.sap.com/saphelp_nwce10/helpdata/en/9a/e8934258a5ca6ae10000000a155106/frameset.htm
I have created java and enterprise application DC and deployed successfully. But while creating CO in design time when i am selecting application and entering class as com.examples.bckgco.UserDetailsCallableObject for Implementation Class Name , and on click next i m getting exception as "can not find this class name". package and class name are correct still getting this excetpion message. Plz help me to resolve this solution.
Regards
Kavita

Hi, kavita.
First, make sure you choosed the correct container when you created the background CO.
Second, make sure your package name was "com.examples.bckgco" and class name was "UserDetailsCallableObject". The exception which you got just means you entered incorrect name.
It doesn`t relate to your program.
Best Regards.
Louis Huang.

Java server page compiler can not find a class defined in a java bean file

I have a jsp file using java bean. The java bean class file is uploaded into the server and also the directory to this java bean .class file is included in the Unix environment CLASSPATH. This .jsp file is registered and should be compiled and excecuted automatically.
WHen I try to invoke this .jsp file, the jsp compiler error, saying the class defined by java bean can not be found. I already include this path in teh CLASSPATH, I thought the jsp compiler will go to the right place according to CLASSPATH to find the referenced class.
Can anyone tell me what I have done wrong or what should I do in order to allow jsp compiler to find the class refrenced by .jsp file and defined by java bean file?
Thank you so much

hello friends,
i am also facing the same problem of not finding bean class files for both jsp and servlet though it is placed in same package. the problem of not finding bean class file for jsp is experienced in Tomcat server only whereas in Blazix, there is no such error and the file is compiled and runs successfully.
i have checked Tomcat properly. there is no error in its configuration also servlets without the use of bean files run successfully. so please can anybody guide me about what is the problem and how to solve it. plz its urgent .

Rmi and classloader: some server instances can not find the class on server

Hi:
I want to migrate my rmi applications from JDK 1.1 to JDK1.2.2. It exists in the following environments:
- there is one authentication server and many application servers, all have binded in the main method
- dynamic loading of the server stubs and interfaces is not used; they are local on the client.
- security manager is enabled only on the server site and the policy file is created.
- all server classes, stubs and interfaces are in the same directory on server site
- the registry and the server are started as follows:
unsetenv CLASSPATH
rmiregistry 1103 &
setenv CLASSPATH ~usr/serverDir:~oracle/jdbc/lib/classes12.zip
java -Djava.rmi.server.codebase=file://~usr/serverDir/
-Djava.rmi.server.hostname=myHost -Djava.security.manager myServer
After starting the client, the rmi client connects to the server and the authentication request comes back with a list of applications.
When the user chooses one of them, the rmi sends the request to thatapplication (e.g., OMSRmiServer_Stub). The application could not find the other class on the sever directory: (the authenication server can find the same class)
java.lang.NoClassDefFoundError: JOMPrepStatement
at java.lang.Class.getFields0(Native Method)
at java.lang.Class.getFields0(Compiled Code)
at java.lang.Class.getDeclaredFields(Compiled Code)
at java.io.ObjectStreamClass$1.run(Compiled Code)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessController.doPrivileged(Compiled Code)
at java.io.ObjectStreamClass.<init>(Compiled Code)
at java.io.ObjectStreamClass.lookupInternal(Compiled Code)
at java.io.ObjectStreamClass.lookup(Compiled Code)
at java.io.ObjectStreamClass.lookupInternal(Compiled Code)
at java.io.ObjectStreamClass.lookup(Compiled Code)
at java.io.ObjectStreamClass.lookupInternal(Compiled Code)
at java.io.ObjectStreamClass.lookup(Compiled Code)
at java.io.ObjectStreamClass.lookupInternal(Compiled Code)
at java.io.ObjectOutputStream.writeObject(Compiled Code)
at sun.rmi.server.UnicastRef.marshalValue(UnicastRef.java:256)
at sun.rmi.server.UnicastRef.invoke(Compiled Code)
at OMSRmiServer_Stub.executeStringSetSelect(Unknown Source)
at OMSDeviceRmiClient.getStatusLOV(OMSDeviceRmiClient.java:196)
at OMSRmiClient.getStatusLOV(OMSRmiClient.java:76)
at OMSDevicePane.listenToTree(Compiled Code)
at OMSDeviceContextPane.initComponents(OMSDeviceContextPane.java:107)
at OMSFrame.jomInit(Compiled Code)
at JOMCountFrame.init(JOMCountFrame.java:190)
at JOMCountFrame.run(JOMCountFrame.java:253)
at java.lang.Thread.run(Thread.java:485)
Any help is appreciated.
- Mahan.

in jdk1.2.2 no need classes12.zip in class path.
just set CLASSPATH=.;
that is enough for solving ur problem
bye
raghu

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.*;
* This program demonstrates how to add simple copy-and-paste capabilities
* to an application.
public class SimpleCutAndPaste extends Frame implements ClipboardOwner
    /** The main method creates a frame and pops it up. */
    public static void main(String[] args) {
     Frame f = new SimpleCutAndPaste();
     f.addWindowListener(new WindowAdapter() {
          public void windowClosing(WindowEvent e) { System.exit(0); }
     f.pack();
     f.setVisible(true);
    /** The text field that holds the text that is cut or pasted */
    TextField field;
     * The constructor builds a very simple test GUI, and registers this object
     * as the ActionListener for the buttons
    public SimpleCutAndPaste() {
     super("SimpleCutAndPaste"); // Window title
     this.setFont(new Font("SansSerif", Font.PLAIN, 18)); // Use a big font
     // Set up the Cut button
     Button copy = new Button("Copy");
     copy.addActionListener(new ActionListener() {
          public void actionPerformed(ActionEvent e) { copy(); }
     this.add(copy, "West");
     // Set up the Paste button
     Button paste = new Button("Paste");
     paste.addActionListener(new ActionListener() {
          public void actionPerformed(ActionEvent e) { paste(); }
     this.add(paste, "East");
     // Set up the text field that they both operate on
     field = new TextField();
     this.add(field, "North");
     * This method takes the current contents of the text field, creates a
     * StringSelection object to represent that string, and puts the
     * StringSelection onto the clipboard
    public void copy() {
     // Get the currently displayed value
     String s = field.getText();
     // Create a StringSelection object to represent the text.
     // StringSelection is a pre-defined class that implements
     // Transferable and ClipboardOwner for us.
     StringSelection ss = new StringSelection(s);
     // Now set the StringSelection object as the contents of the clipboard
     // Also specify that we're the clipboard owner
     this.getToolkit().getSystemClipboard().setContents(ss, this);
     // Highlight the text to indicate it is on the clipboard.
     field.selectAll();
     * Get the contents of the clipboard, and, if we understand the type,
     * display the contents. This method understands strings and file lists.
    public void paste() {
     // Get the clipboard
     Clipboard c = this.getToolkit().getSystemClipboard();
     // Get the contents of the clipboard, as a Transferable object
     Transferable t = c.getContents(this);
     // Find out what kind of data is on the clipboard
     try {
         if (t.isDataFlavorSupported(DataFlavor.stringFlavor)) {
          // If it is a string, then get and display the string
          String s = (String) t.getTransferData(DataFlavor.stringFlavor);
          field.setText(s);
         else if (t.isDataFlavorSupported(DataFlavor.javaFileListFlavor)) {
          // If it is a list of File objects, get the list and display
          // the name of the first file on the list
          java.util.List files = (java.util.List)
              t.getTransferData(DataFlavor.javaFileListFlavor);
          java.io.File file = (java.io.File)files.get(0);
          field.setText(file.getName());
     // If anything goes wrong with the transfer, just beep and do nothing.
     catch (Exception e) { this.getToolkit().beep(); }
     * This method implements the ClipboardOwner interface. It is called when
     * something else is placed on the clipboard.
    public void lostOwnership(Clipboard c, Transferable t) {
     // Un-highlight the text field, since we don't "own" the clipboard
     // anymore, and the text is no longer available to be pasted.
     field.select(0,0);
}

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

Please,please help, this drives me crazy,can not find the class but...

The story is:
I have alot java class files under directory: c:\myproj\com\pin\sa
in each of the file, the package signature is: package com.pin.sa
Then I set the JavaVMInitArgs fVM_args; by setting the classpath to:c:\myproj
then I use: cls = (*fEnv).FindClass("com/pin/sa/frameWork") to find a class file called frameWork, but failed.
then i build a test file called test.class (it is just a simple file pls see below for the code)and put package com.pin.sa in it and put it in directory : c:\myproj\com\pin\sa, this means the test.class is under the same directory as the frameWork.class,
then I use cls = (*fEnv).FindClass("com/pin/sa/test"), and it SUCCEEDED!!!
I really don't understand why like this, they have same package signature and under same directory why different results.
In frameWork file, there are some imported packages, does this matter? And there is a static main() in it.
if you can give an example of how to set the classpath in JavaVMInitArgs fVM_args, and how to deal with the package signature, I will appreciate it very much
==test.java==
package com.pin.sa;
public class test
public void printHello()
System.out.println("Hello World from Java!");
cls = (*fEnv).FindClass("com/pin/sa/test");
cls = (*fEnv).FindClass("com/pin/sa/test");
C:\\myProj\\resiprocate\\myAnalysis\\sipphone\\sipXphone\\main\\softphone\\lib");

Hi Hufuman,
What are the packages that you are using in frameWork Class. Add the class path to those classes also. Also check the name of the .class file is exactly the same as frameWork and not FrameWork or framework etc.
Check whether you have correctly given the package declaration in the frameWork class.
If you dont have any problem, post the frameWork class definition also here or atleast the packages imported and the classpath set for those referred packages.
Dhamo.

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

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

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.

CAN NOT FIND MAIN CLASS

Similar Messages

Maybe you are looking for