Dynamiclally retreiving the main class name

Hi Folks,
I would like to dynamically retrieve the class name of the main class which was invoked. Lets say my class name is HelloWorld. I run it using
java HelloWorld
Now I need to dynamically retrieve the Classname (HelloWorld) using a java program. Can any please let me know how to achieve it.
Regards,
PA

georgemc wrote:
Someone else asked this very recently, but I'm bugggered if I can remember the answer. Well, the most common answer was "Why d'you need to do this?" but someone actually knew how to do it. I think it involved the instrumentation API, but I might be wrong. Pretty sure it wasn't anything to do with reflection, thoughYou are just soooooooooooooo sarcastic, George! I am gonna get one of the moderators out after you ... so watch your step! Regards,
~Bill

Similar Messages

Is it possible to get the main class name in a Thread context ?

for example, i want to get the main class name (the first entry of the program).
public class Test implements Runnable {
     public Test() {}
     public static void main(String[] args) {
          new Thread(new Test()).start();
     public void run() {
          try {
               //Want to get the main class name (not the current class name)
               throw new Throwable();
          } catch (Throwable e) {
               e.printStackTrace();
}

Acutally, i wanna make clear about the concept of a "Thread"
Is it true that ..
the main() method is a thread , once I create another thread in the program , both of (or all of them) will contains it owns stack exception information ?
My english is poor, please try to understand it. Thx

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.
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java version "1.6.0_24"
Java(TM) SE Runtime Environment (build 1.6.0_24-b07)
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Error Message
=========
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(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\
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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
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AddJavaLibFile ../../jdev/lib/xmleditor.jar
AddJavaLibFile ../../ide/lib/oicons.jar
AddJavaLibFile ../../jlib/jewt4.jar
AddJavaLibFile ../../jlib/share.jar
AddJavaLibFile ../ide/jlib/xmlef.jar
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AddJavaLibFile ../../sqldeveloper/lib/oracle.dbtools.logging.jar
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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

Could not find the main class: SearchExcel. Program will exit. ????

sekic0429{uabudd_milou}[w10/rbssw/2.0] pwd
/tmp/MyJava/jexcelapi
sekic0429{uabudd_milou}[w10/rbssw/2.0] printenv CLASSPATH
/tmp/MyJava/excelapi:/app/jdk/1.6.0_16/jre/lib:/app/jdk/1.6.0_16/lib
sekic0429{uabudd_milou}[w10/rbssw/2.0] ls
build ExcelSearch.java index.html resources SearchExcel.java~ tutorial.html
docs ExelSearch.java~ jxl.jar SearchExcel.class src workbook.dtd
ExcelSearch.class formatworkbook.dtd jxlrwtest.xls SearchExcel.java TestSpecification.xls
sekic0429{uabudd_milou}[w10/rbssw/2.0] javac -extdirs . ExcelSearch.java
sekic0429{uabudd_milou}[w10/rbssw/2.0]
sekic0429{uabudd_milou}[w10/rbssw/2.0] java ExcelSearch
Exception in thread "main" java.lang.NoClassDefFoundError: ExcelSearch
Caused by: java.lang.ClassNotFoundException: ExcelSearch
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: ExcelSearch. Program will exit.
sekic0429{uabudd_milou}[w10/rbssw/2.0] cat ExcelSearch.java
import java.io.File;
import java.io.IOException;
import java.util.Date;
import jxl.*;
import jxl.read.biff.BiffException;
public class ExcelSearch
public static void main(String[] args)
try
Workbook workbook = Workbook.getWorkbook(new File("TestSpecification.xls"));
catch (IOException e)
e.printStackTrace();
catch (BiffException e)
e.printStackTrace();
Regards Peter, hope for answer

r035198x wrote:
Where is SearchExcel.class?Excellent question, though I think I spotted a problem with the cp supplied.
Note the documentation for -cp state (in part)
For example, if directory foo contains a.jar and b.JAR, then the class path element foo/* is expanded to a A.jar:b.JAR, except that the order of jar files is unspecified.So instead of this..
java -cp /tmp/MyJava/excelapi:/app/jdk/1.6.0_16/jre/lib:/app/jdk/1.6.0_16/lib SearchExcel..try this..
java -cp /tmp/MyJava/excelapi/*:/app/jdk/1.6.0_16/jre/lib:/app/jdk/1.6.0_16/lib SearchExcelNotes:
1) Adding the JRE classes to the classpath should not be necessary, but I left the rest of the cp unaltered to highlight the one specific difference I am suggesting.
2) When posting code, code snippets, HTML/XML or input/output, please use the code tags. The code tags help retain the indentation and formatting of the sample. To use them, select the sample text and click the CODE button.
If that still fails, tell us more specifically where the SearchExcel class is by copy/pasting the output (within code tags) of the command..
prompt>jar -tvf mysearchexcel.jarWhere, of course, you replace 'mysearchexcel.jar' with the actual Jar name it is supposed to be located in.
Edit 1:
Changed JavaDocs -> documentation.
Edited by: AndrewThompson64 on Jan 11, 2010 7:12 PM

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.

"Could not find the main class" when running a jar

Hi, I'm trying to create and run a jar from my application, but I can't figure out how to properly set an entry-point. Looking at the Java Tutorials http://java.sun.com/docs/books/tutorial/deployment/jar/index.html I still can't get it to work.
I have a directory myApp, which contains a directory images and some class files, including mainClass.class. I also have a manifest Manifest.txt in the directory myApp with the following line:
Main-Class: mainClass.class
+ one empty line
I create a jar successfully, while inside the myApp directory, with the following command:
jar cfm myApp.jar Manifest.txt *.class images\*.*
I then proceed to run the jar with the following command:
java -jar myApp.jar
and receive the following error:
Exception in thread "main" java.lang.NoClassDefFoundError: myApp/class
My completely uneducated guess is that there is something wrong with my manifest. The tutorial says that the line should be:
Main-Class: MyPackage.MyClass
I'm assuming that I get the error because I didn't specify a package, which I didn't do because I didn't know what to put there. Do I even have a package?
Can anyone tell me what I've done wrong? thanks.
Message was edited by:
SmurfZG

One problem is you are specifying a file name instead of a class name. It probably should beMain-Class: mainClassA good test is to run your app before jaring it - if you run it with "java mainClass" then the Main-Class attribute must be mainClass.
Also class naming conventions say that class names should start with a capital letter - MainClass for example. It is just a convention, but it is easier to get help when you follow conventions.

[Jar Executable] Could not find the main class. Progam will exit.

Hello,
I am a French person. Excuse me for my English who is not perfect.
I seek to create an achievable "jar". I followed the instructions given in the url http://java.developpez.com/faq/java/?page=execution#creationJar, and on the site of Sun.
I have today only one class which I posed in a specific repertory "Class".
Appli
|__Class
|__Src
|__META-INFThe contents of my "Manifest" is stored in repertory META-INF with the name "Commission2007.MF" and its contents are as follows:
Manifest-Version: 1.0
Created-By: 1.5.0 (Sun Microsystems Inc.)
Main-Class: Commission2007
.I've left the space line at the end of the file.
Here the result of execution of my order "jar":
C:\#Java Dev\2007_Commissionnements>jar cvfm Commission2007.jar META-INF/Commission2007.MF -C Class/ .
manifest ajout�
ajout : Class/./(entr�e = 0) (sortie = 0)(0% stock�)
ajout : Class/./Commission2007.class(entr�e = 9060) (sortie = 4547)(49% compress�s)I controlled the assignment of the extension "jar" in "Working station = > Tools = > Files Option = > Files Type = > .jar Selection = > Advance =
Open = > Change = >" C:\Program Files\Java\jre1.6.0\bin\javaw.exe "- gravel bank" %1 "% *". Thus not of problem on this side there!When I double click on the file "jar" lately created, I have the error message according to: "Could not find the main class. Progam will exit. " I do not understand the reason of this error. I consulted all the subjects on the treating Net of this subject but without result. I thus call upon you.
Perhaps that the cause is in my code which however functions perfectly when I carry out it with the order: "Commission2007 java". The class "hand" is quite present to see the code below. You can find the totality of my code on the bond http://www.developpez.net/forums/showpost.php?p=1870361&postcount=74
import �
public class Commission2007 extends Frame implements ActionListener, WindowListener
     �
     // Construction de la class EdText
     // D�finition et affichage de la bo�te de dialogue
     Commission2007()
     �
     // D�finition d'une frame pour l'application et affichage de la
     // bo�te de dialogue
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}I thank you in advance for your assistance.
Cordially, Gilles.

Salut,
It has been my experience that it is never a good idea to name your .MF file anything else other than MANIFEST.MF.
Try naming your .MF file MANIFEST.MF and rebuild your JAR.
Bon chance.

How do I declare a native method outside of the main class?

Hi
This is a JNI particular question.
I am having a problem with generating the header .h file after executing javah. The file is generated correctly but is empty under certain circumstances.
This is the 'empty file:
=================
/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class gui_GuiMain */
#ifndef Includedgui_GuiMain
#define Includedgui_GuiMain
#ifdef __cplusplus
extern "C" {
#endif
#ifdef __cplusplus
#endif
#endif
This is what it should look like:
=========================
/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class gui_GuiMain */
#ifndef Includedgui_GuiMain
#define Includedgui_GuiMain
#ifdef __cplusplus
extern "C" {
#endif
* Class: gui_GuiMain
* Method: getValueOIDTestMIB
* Signature: ()V
JNIEXPORT void JNICALL Java_gui_GuiMain_getValueOIDTestMIB
(JNIEnv *, jobject);
#ifdef __cplusplus
#endif
#endif
The header file becomes "empty" when the native function getValueOIDTestMIB is declared in a different class than what my main() function is declared in.
For example something like this will work:
class Main
public native void getValueOIDTestMIB
static {
System.loadLibrary("libsnmp++");
//............some more functions etc.............
public static void main(String[] args)
//............some more stuff...........................
But when I declare this:
public native void getValueOIDTestMIB
static {
System.loadLibrary("libsnmp++");
outside the class, in another class within the same package, nothing happens.
I am probabily doing something stupid. Can somebody help or give me some guidance to where I should look. I come from a C++ background, not a guru in Java.
Thanks

You need to run javah and give it as a parameter the full class name of the class which contains the native methods.
For example (if your class is called A and its package is a.b.c)
javah -jni a.b.c.A

Deployment - "Could not find the main class."

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Java Virtual Machine Launcher
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-jar: illegal argument
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If you create a new project in JDeveloper.
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[\pre]
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Hey,
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* and open the template in the editor.
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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.
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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:
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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.

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/

JRE doesn't find the main class inside a JAR archive file

Hello everybody,
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java -jar TestApplication.jar
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   at java.lang.ClassLoader.loadClass(libgcj.so.81)
   at java.lang.ClassLoader.loadClass(libgcj.so.81)
   at gnu.java.lang.MainThread.run(libgcj.so.81)I know that these errors often come when the class path is not set in the right way, and using a single java file, you can fix this by passing the parameter "-cp ."
I tried this with the jar file but it does not work and using "-cp TestApplication.jar tst/Benchmark" didn't work either.
Inside the jar file I have the META-INF Folder and a "tst" Folder which contains all my class files. And I've set tst.Benchmark as the main class, this also stands in the manifest file correctly.
Do you have any ideas what could be wrong?
Greetings JavanianGuy

This line
at gnu.java.lang.MainThread.run(libgcj.so.81)says that you're using GNU's Java, not Sun's Java. They are not the same. GNU Java is incomplete.
You'll need to ask this question at the GNU Java site.
Recommendation: Use Sun's Java

Java .class files - Moving the Main Class .class file to a new location

Novice question....so much so that I hope it's even coherent...
In a Java program which references many associated .class files (e.g. bicycleMain.class, bicycleSub1.class, bicycleSub2.class, etc....), do the associated .class files always have to be located in the same directory as the Main .class file?
What I'm getting at is - If I've developed an application consisting of several .class files on my own Windows PC and I want to put the compiled application out on our Windows File Server so that anyone can execute my application, how would I go about doing this?
Say I put the compiled .class files in H:\PROJECTS\JAVA\COMPILED\, will other people be able to execute the application from their PCs by simply issuing the command line:
'java h:\projects\java\compiled\bicycleMain'
Any insights would be very helpful in getting me oriented. Thanks in advance.

Interesting...so are you saying the command line might look something like this:
java -classpath h:\projects\java\compiled bicycleMain
And if I want other people to be able to execute the application without specifying the -classpath option then they would need to manually update the ClassPath environment variable on their individual PCs first?

How to get the current class name in static method?

Hi,
I'd like to get the current class name in a static method. This class is intended to be extended. So I would expect that the subclass need not to override this method and at the runtime, the method can get the subclass name.
getClass() doesn't work, because it is not a static method.
I would suggest Java to make getClass() static. It makes sense.
But in the mean time, does anybody give an idea to work around it?
Thank you,
Bill

Why not create an instance in a static method and use getClass() of the instance?
public class Test {
public static Class getClassName() {
return new Test().getClass();

Dynamiclally retreiving the main class name

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