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  2. RPG400-L
  3. November 2014

Re: jTDS JDBC driver with IBM i 7.1 using JDBCR4

Hello René,

The important thing for this is to know what error message is showing on your display. I'm not sure if we are seeing the whole message, since it starts with "at", which looks like something from the middle of the stack dump.

Can you please try running your application like this:

1) Start with a fresh session (SIGNOFF, then SIGNON to start a fresh session)

2) Type OVRPRTF FILE(STDOUT) TOFILE(QSYSPRT) HOLD(*YES) OVRSCOPE(*JOB)

3) Run your program.

4) Sign off.

This should cause the error messages to go to a spooled file instead of your display, and the spooled file should contain the entire message.

From the part you did have, it looks like UnsupportedClassVersionError -- this means that the version of the Java class you are using is not compatible with the version of the JVM you are running. It's not clear to me if this is the right message, however, since it appears in the middle of the output you sent instead of at the start.

Also, not sure that I would set a CLASSPATH in a subprocedure...? Keep in mind that the first time RPG uses Java in a given job, it loads the JVM into memory, and the CLASSPATH is only read at that time. That means that if you run your subprocedure in a job where the JVM has already been loaded (from running any prior Java code) it will not check CLASSPATH a second time, so any changes to the CLASSPATH will be ignored. (Until the job is ended/restarted.)


On 11/14/2014 3:16 PM, René A Valencourt wrote:
This question is for Scott Klement, or anyone else who may have solved
something like this...

We have a new Power 8 IBM i running v7r1. QShell tells me that we are
running Java version "1.6.0" (which I guess is Java 6).

java version "1.6.0"
Java(TM) SE Runtime Environment (build pap3260sr16-20140418_01(SR16))
IBM J9 VM (build 2.4, JRE 1.6.0 IBM J9 2.4 OS/400 ppc-32
jvmap3260sr16-20140418_01 (JIT enabled, AOT enabled)
J9VM - 20140416_196573
JIT - r9_20130920_46510ifx5
GC - GA24_Java6_SR16_20140416_1614_B196573)
JCL - 20140406_01

I want to query a MS SQL Server 2005 database running on a Windows server
from an RPG ILE program. I created a program based on mssqltest.rpgle that
Scott Klement made available. I created an IFS directory called /javasql
and put various driver .jar files there:
· sqljdbc.jar
· jtds-1.2.5.jar
· jtds-1.2.6.jar
· jtds-1.2.7.jar
· jtds-1.2.8.jar
· jtds-1.3.0.jar
· jtds-1.3.1.jar

When I specify Microsoft's driver this works every time. Over the last
couple of days, 'jtds-1.2.5.jar' has worked for me several dozen times (the
later versions all got either the "major version" or "major-minor version"
error). Now today only the Microsoft driver works.

I believe that the only difference be that at day's end yesterday I made
changes in my program to put the code that checks and alters the CLASSPATH
variable into a subprocedure, and I put the code that opens the JDBC
connection into another subprocedure. However, I'm not sure that this could
cause this problem, and the program appears to run correctly with expected
values in the variables.

Before I run my program, QShell shows no CLASSPATH variable, afterwards
there is one, so I know that code works:

CLASSPATH=.::/javasql/jtds-1.2.5.jar

My program's OpenJDBCconnection subprocedure calls the JDBC_ConnProp
subprocedure inside the JDBCR4 service program. Through RDi debug, I could
see that just before the execution of 'new_Driver' subprocedure in JDBCR4,
the path to the Driver class was set as expected
('net.sourceforge.jtds.jdbc.Driver'), and the URL also
('jdbc:jtds:sqlserver://172.18.120.21:1433'), though the program never gets
to use it if it can't instantiate the driver...

// Find & Instantiate Driver

drv = new_Driver(drivname);
if (drv = *NULL);
jdbc_end_object_group();
return *NULL;
endif;

The program fails inside the JDBCR4 "new_Driver" subprocedure, at this code:

cls = FindClass(env: drv_name);
if (jni_CheckError(*omit));
return *NULL;
endif;

The value of 'drv_name' just before getting translated to ASCII was
'net/sourceforge/jtds/jdbc/Driver'.

With the failure to instantiate the driver I get this display in my IBM i
session:

at java.lang.ClassLoader.loadClass(ClassLoader.java:643)
Exception in thread "main" java.lang.UnsupportedClassVersionError:
JVMCFRE003 bad major version; class=net/sourceforge/jtds/jdbc/Driver,
offset=6
at java.lang.ClassLoader.defineClass(ClassLoader.java:287)
at
java.security.SecureClassLoader.defineClass(SecureClassLoader.java:74)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:540)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:451)
at java.net.URLClassLoader.access$300(URLClassLoader.java:79)
at java.net.URLClassLoader$ClassFinder.run(URLClassLoader.java:1038)
at
java.security.AccessController.doPrivileged(AccessController.java:362)
at java.net.URLClassLoader.findClass(URLClassLoader.java:429)
at sun.misc.Launcher$ExtClassLoader.findClass(Launcher.java:281)
at java.lang.ClassLoader.loadClass(ClassLoader.java:677)
at java.lang.ClassLoader.loadClass(ClassLoader.java:669)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:358)
at java.lang.ClassLoader.loadClass(ClassLoader.java:643)

As I mentioned, Microsoft's driver works without fail, and the jTDS 1.2.5
driver was working yesterday!

René A Valencourt, CCP, MCTS
Senior Programmer/Analyst
IS Department
CTB
CTB, Inc.
A Berkshire Hathaway Company


Re: Quick JDBCR4 questions

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* Subject: Re: Quick JDBCR4 questions
* From: Scott Klement <rpg400-l@xxxxxxxxxxxxxxxx>
* Date: Thu, 13 Feb 2014 14:51:37 -0600
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fixed <http://archive.midrange.com/rpg400-l/201402/msg00061.html>
_____

Chuck,

JDBCR4 works with Java 1.3 or higher. However, the individual database
drivers also have their requirements.

In your case, it sounds like you are using the jTDS driver (for Microsoft
SQL Server).

If I recall correctly the version of Java that jTDS requires varies with the
version of jTDS that you're using. jTDS 1.3.x requires Java 7, and jTDS
1.2.x works with older versions of Java.

So, you'll either want to install Java 7 (sometimes called "1.7") and if
necessary, set your JAVA_HOME environment variable to point to it... or get
an older version of jTDS. I used 1.2.5 successfully with older JVMs.

Good luck!



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