Re: Java class not found but it's in the default path?

Hi Barbara,

As I mentioned, I'm not familiar with Scott's work; from what I can
tell, I would normally do things ANOTHER WAY. But I wouldn't be surprised
if your guess is correct.

It's (fortunately) been a long time since I've received
NoClassDefFoundError. If I'm not mistaken, the ones I got typically
happened when I compiled against a current jar (using new functionality) and
ran against an older one. Notice that NoClassDefFoundError always, or
should I say *only*, occurs at run time.


Joe Sam

Joe Sam Shirah - http://www.conceptgo.com
conceptGO - Consulting/Development/Outsourcing
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----- Original Message ----- From: "Barbara Morris" <bmorris@xxxxxxxxxx>
To: <java400-l@xxxxxxxxxxxx>
Sent: Thursday, November 08, 2007 1:36 PM
Subject: Re: Java class not found but it's in the default path?

Joe Sam Shirah wrote:

I'm not familiar with Scott Klement's JDBC driver, and I'm a little
confused by the implication that his (or any custom) driver is in
jt400.jar.
Regardless, the thing to note is that you are getting a No *ClassDef*
Found error, not a ClassNotFoundException.

The javadocs for NoClassDefFoundError say: "The searched-for class
definition existed when the currently executing
class was compiled, but the definition can no longer be found. " I'll
refer
you to:
...

Joe Sam, that's interesting. I didn't realize there were two exceptions
associated with class-not-found. (I don't know whether I would have
noticed if I ever got a ClassNotFound instead of a NoClassDefFound.)

I think Scott's code uses JNI to make native method calls to an existing
JDBC driver; I have only ever seen NoClassDefFound when a class is not
found for a native method call. I'm just guessing - maybe the class
loader used by JNI for native method calls goes through the same path as
for method calls in compiled Java classes, so it gives NoClassDefFound.

For example, when I call the following RPG program, which tries to call
method mth() in class NoSuchClass, the call fails with
java.lang.NoClassDefFoundError: NoSuchClass.

D meth pr extproc(*java:'NoSuchClass':'mth')
D static
/free
mth();
return;

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