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Jar File Error: Could not find main class.

Posted on 2006-06-09
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Last Modified: 2013-11-23
I build my jar file using BENV.
It doesn't work in a directory with "src" in it.  I.E. C:views\ifd\src\copper
All other times it works.  
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Question by:tjwallace05
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Expert Comment

by:hoomanv
ID: 16872789
how do you run it ? by double clicking ? or java -jar yourjar.jar ?
did you specified its main class in MANIFEST.MF
  Manifest-Version: 1.2
  Main-Class: DiveLog
and how do you create jar ? jar -cmf yourjar.jar MANIFEST.MF *.class
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Expert Comment

by:hoomanv
ID: 16872816
typo --> jar -cmf should be jar -cfm
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by:hoomanv
ID: 16872912
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Author Comment

by:tjwallace05
ID: 16873226
To make my jar, I use a program call BENV which is just a build enviroment.
I specified my main class in the Manifest file.
I run the jar file both by double clicking it and by running a batch file from the commandline.
It will not run (double clicking) in a directory with "src" in it but it will run anywhere else.
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Expert Comment

by:hoomanv
ID: 16873422
please post the content of the manifest along with the batch file

> It will not run (double clicking) in a directory with "src" in it but it will run anywhere else.
you mean the existance of another folder named "src" near the jar, does impact on the execution ?
could you explain more in which circumstance(s) it fails to run
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Author Comment

by:tjwallace05
ID: 16873826
this is the batch file I use to create the jar file.
@echo off
:: This script is used to launch the make.  Type mk /? for help
::

:: Test if the environment is set
IF "/%BENV_LATEST_ROOT%"=="/" GOTO error
IF "%OS%"=="Windows_NT" which java.exe 2>NUL 1>NUL
IF NOT "%OS%"=="Windows_NT" which java.exe >NUL
if ERRORLEVEL 1 goto notfound
IF "%OS%"=="Windows_NT" which javac.exe 2>NUL 1>NUL
IF NOT "%OS%"=="Windows_NT" which javac.exe >NUL
if ERRORLEVEL 1 goto notfound

:: Launch make
call findroot
sh %BENV_WORKAREA_ROOT%\build\gnu\bin\unix\Mk -T win32 %1 %2 %3 %4 %5 %6 %7 %8 %9
goto exit
:notfound
echo:
echo:You must first set JAVA Development environment by updating your PATH
echo:to include the JVM, the JAVA compiler, and SDK tools.
echo:
goto exit
:error
echo:
echo:You must first set the variable: BENV_LATEST_ROOT.
echo:
:exit


Batch file to run jar file:
@echo off
:: Batch file to set alias for executing the java application
::

:: Name of the jarfile
set jarname=jxcodegui.jar

:: Set alias
doskey jxcodegui=java -jar %jarname% $*

echo:Alias 'jxcode' has been set.  Run the command again to execute
echo:the application.
echo:
echo:To update the 'jxcode' alias. Run jxcode.bat again
echo:

Manifest file:
Manifest-Version: 1.0
Created-By: 1.4.2_11 (Sun Microsystems Inc.)
Main-Class: JXCodeGuiMain

My program generates skeleton files in the folder from which it is executed.  So if I run the program from a folder like C:\views\codegen\projects it will run but if I place the jar file in C:\views\codegen\src it will not run.  If "src" is found anywhere in the path name, it will not run.  Could not find main class is displayed.
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Expert Comment

by:hoomanv
ID: 16873930
> If "src" is found anywhere in the path name, it will not run
I cant understand what is the correlation of src in path with running of jar ?
I is more likely something that is thrown by the application not by the java runtime
what is the exact phrase of the error message ?
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Author Comment

by:tjwallace05
ID: 16874011
Java Virtual Machine Launcher

Could not find the main class.  Program will exit
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Accepted Solution

by:
hoomanv earned 2000 total points
ID: 16874193
this is definitively a classpath issue
can you run the code this way: java -cp jxcodegui.jar JXCodeGuiMain
you should first go to the directory where jxcodegui.jar is located otherwise the full path to jxcodegui.jar is needed
(I assumed JXCodeGuiMain is not in a package)
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Author Comment

by:tjwallace05
ID: 16874319
Thanks a lot.  That did it.
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