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Posted to dev@ant.apache.org by Jon McLennan <jm...@clear2pay.com> on 2005/09/27 09:47:21 UTC
NoClassDefFoundError when loading class from -lib
I posted this to the users list, but didn't get any response. Maybe
someone on this list can help.
I've taken the source for org.apache.tools.ant.Launcher and modified it
to call my own version of Main.java. Essentially, the only change I made
with that class is to allow the user to specify which startup class is
to be run. (The default is the standard org.apache.tools.ant.Main.) My
version of Main can create menus from targets in the build file (plus
some other features). I use log4j for logging debugging messages.
The problem I'm running into is when I call this line:
Class mainClass = Class.forName(classmain, false, loader);
// classmain = my Main.java
I get this error:
java.lang.NoClassDefFoundError: org/apache/log4j/Category
at java.lang.Class.newInstance0(Native Method)
at java.lang.Class.newInstance(Class.java:232)
at com.clear2pay.releng.Launcher.run(Launcher.java:351)
at com.clear2pay.releng.Launcher.main(Launcher.java:75)
I'm running Ant 1.6.1 (installed at D:\java\ant-1.6.1) and my external
lib directory (D:\java\lib) is passed to Ant via the -lib command line
arg. I have log4j-1.2.6.jar in that directory.
This is the command line I use:
java !ANT_OPTS! -classpath
"d:\java\lib\releng.jar;
d:\java\apache-ant-1.6.1\lib\ant.jar;
d:\java\apache-ant-1.6.1\lib\ant-launcher.jar;
d:\java\apache-ant-1.6.1\lib\xml-apis.jar;
d:\bea\jdk131\jre\lib\rt.jar;
d:\bea\jdk131\lib\dt.jar;
d:\bea\jdk131\lib\tools.jar;
d:\bea\jdk131\jre\lib\i18n.jar;" com.clear2pay.releng.Launcher
-lib "D:\java\lib"
-mc com.clear2pay.releng.Main
I put some debugging statements in com.clear2pay.releng.Launcher to see
if org.apache.log4j.Category has been loaded by the ClassLoader
Class myClass = loader.loadClass("org.apache.log4j.Category");
System.out.println("myClass = " + myClass);
which outputs:
myClass = class org.apache.log4j.Category
I even tested it by listing the methods available from that class.
So what I don't understand is, why is com.clear2pay.releng.Launcher able
to find org.apache.log4j.Category when I get it from the loader, but it
can't be found when I load a class that imports it? I can get this to
work if I put all external jars I need directly in the Classpath, but
this can cause problems on Windows if the value of Classpath gets too
long and I'd like to avoid that.
Jon
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Re: NoClassDefFoundError when loading class from -lib
Posted by Martin Gainty <mg...@hotmail.com>.
Jon-
Follow the log4j Install doc at
http://www.ingrid.org/jajakarta/log4j/jakarta-log4j-1.1.3/INSTALL
Marty-
"Life is what happens when you're busy making other plans" - John Lennon
----- Original Message -----
From: "Jon McLennan" <jm...@clear2pay.com>
To: <de...@ant.apache.org>
Sent: Tuesday, September 27, 2005 3:47 AM
Subject: NoClassDefFoundError when loading class from -lib
>I posted this to the users list, but didn't get any response. Maybe
> someone on this list can help.
>
> I've taken the source for org.apache.tools.ant.Launcher and modified it
> to call my own version of Main.java. Essentially, the only change I made
> with that class is to allow the user to specify which startup class is
> to be run. (The default is the standard org.apache.tools.ant.Main.) My
> version of Main can create menus from targets in the build file (plus
> some other features). I use log4j for logging debugging messages.
>
> The problem I'm running into is when I call this line:
>
> Class mainClass = Class.forName(classmain, false, loader);
> // classmain = my Main.java
>
> I get this error:
>
> java.lang.NoClassDefFoundError: org/apache/log4j/Category
> at java.lang.Class.newInstance0(Native Method)
> at java.lang.Class.newInstance(Class.java:232)
> at com.clear2pay.releng.Launcher.run(Launcher.java:351)
> at com.clear2pay.releng.Launcher.main(Launcher.java:75)
>
> I'm running Ant 1.6.1 (installed at D:\java\ant-1.6.1) and my external
> lib directory (D:\java\lib) is passed to Ant via the -lib command line
> arg. I have log4j-1.2.6.jar in that directory.
>
> This is the command line I use:
>
> java !ANT_OPTS! -classpath
> "d:\java\lib\releng.jar;
> d:\java\apache-ant-1.6.1\lib\ant.jar;
> d:\java\apache-ant-1.6.1\lib\ant-launcher.jar;
> d:\java\apache-ant-1.6.1\lib\xml-apis.jar;
> d:\bea\jdk131\jre\lib\rt.jar;
> d:\bea\jdk131\lib\dt.jar;
> d:\bea\jdk131\lib\tools.jar;
> d:\bea\jdk131\jre\lib\i18n.jar;" com.clear2pay.releng.Launcher
> -lib "D:\java\lib"
> -mc com.clear2pay.releng.Main
>
>
> I put some debugging statements in com.clear2pay.releng.Launcher to see
> if org.apache.log4j.Category has been loaded by the ClassLoader
>
> Class myClass = loader.loadClass("org.apache.log4j.Category");
> System.out.println("myClass = " + myClass);
>
> which outputs:
>
> myClass = class org.apache.log4j.Category
>
> I even tested it by listing the methods available from that class.
>
> So what I don't understand is, why is com.clear2pay.releng.Launcher able
> to find org.apache.log4j.Category when I get it from the loader, but it
> can't be found when I load a class that imports it? I can get this to
> work if I put all external jars I need directly in the Classpath, but
> this can cause problems on Windows if the value of Classpath gets too
> long and I'd like to avoid that.
>
> Jon
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: dev-unsubscribe@ant.apache.org
> For additional commands, e-mail: dev-help@ant.apache.org
>
>
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