Re: Simple test Java app runs fine under Eclipse, and from a WinDozecommand line, but fails on the 400.

Look at the *second* attempt though, after he added jdk6 to the classpath. It indicates a Class Not Found error NOT an Unsupported Class Version error. He needs to add the folder where the .class file resides to his class path. Even if it is the IFS 'root' folder.

Pete Helgren
Value Added Software, Inc
www.petesworkshop.com
GIAC Secure Software Programmer-Java


On 6/18/2012 2:33 PM, Joe Sam Shirah wrote:

Hi James,

As David mentioned, first make sure you're using binary mode for FTP.
That's just a checkoff item.

If so, look at the error message: java.lang.UnsupportedClassVersionError

At JDK 1.5, changes were made to the binary format and previous JVM's
won't run the program. That's what it sounds like. Run java -version (
actually JAVA *VERSION on the AS/400 ) to see what version you're using. If
below 1.5, you'll need to recompile with a pre 1.5 version or make sure
you're running a 1.5+ version.

As to the java.lang.NoClassDefFoundError, looks like you gave it the
classpath to the version of the JVM you're expecting, but not to the class
you are running. This is a major reason I always ask, why do you have
multiple Java installations? because the system defaults to sometimes
unexpected versions. If only one is installed, that's what it will use.

And, to others, yes I'm aware that at least some versions of WebSphere
( and possibly other programs ) insist on specific versions. Poor ( or
predatory ) programming practice IMO. Yet another reason I recommend
running Java on another box and use JTOpen for AS/400 operations.


Joe Sam

Joe Sam Shirah - www.conceptgo.com (904) 302-6870
conceptGO - Consulting/Development/Outsourcing
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-----Original Message-----
From: James Lampert
Sent: Monday, June 18, 2012 2:51 PM
To: Java Programming on and around the IBM i
Subject: Simple test Java app runs fine under Eclipse, and from a
WinDozecommand line, but fails on the 400.

I have a simple Java 6 test program, just one class:

import java.nio.charset.*;
public class Test18jn2012 {
public static void main(String[] args) {
String str = "I like Spam.";
byte[] bytes;
bytes = str.getBytes(Charset.defaultCharset());
for (int i=0; i< bytes.length; i++) System.out.print(bytes[i] + "
"); System.out.println();
}
}

It executes just fine in Eclipse. It executes just fine on a WinDoze
command line, even if I move it to a different directory from where I'd
compiled it into.

But when I FTP Test18jn2012.class to the IFS root on our 400, and I try
java Test18jn2012
from either a regular command line or a QShell command line, I get:

Exception in thread "main" java.lang.UnsupportedClassVersionError:
(Test18jn2012) bad major version at offset=6
at java.lang.ClassLoader.defineClassImpl(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:267)
at
java.security.SecureClassLoader.defineClass(SecureClassLoader.java:151)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:600)
at java.net.URLClassLoader.access$400(URLClassLoader.java:124)
at
java.net.URLClassLoader$ClassFinder.run(URLClassLoader.java:1055)
at
java.security.AccessController.doPrivileged(AccessController.java:274)
at java.net.URLClassLoader.findClass(URLClassLoader.java:492)
at java.lang.ClassLoader.loadClass(ClassLoader.java:640)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
at java.lang.ClassLoader.loadClass(ClassLoader.java:606)
Java program completed with exit code 1

and if I try
JAVA CLASS(Test18jn2012) CLASSPATH('/qibm/ProdData/Java400/jdk6')
I get

Exception in thread "main" java.lang.NoClassDefFoundError: Test18jn2012
Caused by: java.lang.ClassNotFoundException: Test18jn2012
at java.net.URLClassLoader.findClass(URLClassLoader.java:497)
at java.lang.ClassLoader.loadClass(ClassLoader.java:640)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
at java.lang.ClassLoader.loadClass(ClassLoader.java:606)
Java program completed with exit code 1

I'm obviously doing something wrong, but WHAT?

--
JHHL