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Re: Using apache.commons.cli with Java 1.4.2

by esharris :: Rate this Message:

ebourg wrote:

esharris a écrit :
> I'm having difficulty using apache.commons.cli with Java 1.4.2. I used
> Eclipse to develop a simple program that uses apache.commons.cli. The
> program works within the Eclipse IDE. However, when I export the program as
> a Jar file and try to run the Jar from the command line (DOS or Unix). I get
> a NoClassDefFoundErrorerror wrt the CommandLineParser. (In another program
> that uses apache.commons.cli, running the jar file triggers the
> NoClassDefFoundErrorwrt HelpFormatter. So, I think java punts on the first
> class it sees containing a problem.)
>
> I also extracted the apache.commons.cli source and built a Jar from it.
> Strangely, I couldn't compile my program using my cli jar, instead on the
> standard jar. When I extract classes from my cli jar, I noticed some of the
> classes in apache.commons.cli are absent. I don't see anything peculiar in
> the source.
>

I don't know how your application is packaged, but did you simply try to
put the commons-cli.jar file downloaded from
http://commons.apache.org/cli in your classpath ?

Emmanuel Bourg

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Yes. I put the jar in my classpath. To accomplish this, I used the -classpath option in java. Then, as an alternate, I updated the CLASSPATH environment variable. I did this in both DOS and UNIX. And I had colleagues try to get the jar to work under 1.4.2. One colleague also spent time extracting the classes from the jar and putting the classes in the class path.

According to this site, ...

http://www.jroller.com/sjivan/entry/difference_between_classnotfoundexception_and_noclassdeffounderror

... you don't want to confuse ClassNotFoundException with the NoClassDefFoundError error. NoClassDefFoundError indicates that the class CommandLineParser was found by the ClassLoader. However, when trying to load the class, the ClassLoader ran into an error reading the class definition. So I am assuming the problem is not in the class path. If it was a problem with the class path, I would get the ClassNotFoundException.

IMHO, NoClassDefFoundError is hard to debug.

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