|
I ran this for FYI just to see what our machine said......
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_16-b05) Classic VM (build 1.4, build JDK-1.4, native threads, jitc_de)
That looks wrong......
then again, since I have no clue about Java, I am only guessing.
From: Pete Helgren <Pete@xxxxxxxxxx> To: RPG programming on the AS400 / iSeries <rpg400-l@xxxxxxxxxxxx> Date: 10/29/2008 04:37 PM Subject: Re: Calling Java from RPG
----------------------------------------------------------------------
What java version is i5/OS running? Quickest way to find out is to run
QSH and then type: java -version at the qsh command line.
Most like you are using a Java 5 specific method. The project build is
one thing. The actual execution of the class is another. Check to see
what i5/OS is running for the java version.
Pete
Nick Arndt wrote:
> Thanks for the help so far.
>
> I now can find my class, but it gives me a
> java.lang.UnsupportedClassVersionError
>
> The java program was created using RDi, I have set the project to
1.3,1.4
> and 5.0 but each time I get the same error.
> Any Idea?
>
> Thanks.
>
> On Wed, Oct 29, 2008 at 3:11 PM, Pete Helgren <Pete@xxxxxxxxxx> wrote:
>
> >> Nick,
>>
>> Barbara has already given you the key to solving the issue. This
>> particular issue is one that comes up in Java pretty often,
particularly
>> in learning curve mode.
>>
>> Java needs to find the class and the classpath is the only way. So if
>> you have only /JavaSrc on your classpath, all class resolution will
>> include that folder to begin with. But this isn't always clear because
>> you may just decide to copy a class file from one directory to another
>> and still expect it to work, just like copying an executable or batch
>> file from one folder to another works with other programs. Java is
>> different because it has a "package" declaration in the java source
>> itself that it uses to resolve the class. So if your java source has a
>> package declaration, the java class file has to be in a folder with the
>> same structure as the package. I won't go into the details as to why
>> this is necessary but take it as a "given" for now. There are other
ways
>> to load classes but we won't go into that either.
>>
>> So if you decide to create a java program with the package name of
>> "programs.nick.levenshtein" and create a class using that package name
>> and the class is called MyClass, then if your classpath has /JavaSrc it
>> in, your JavaSrc folder must also have a subfolder structure of
>> /programs/nick/levenshtein/ and the MyClass.class file should be in it.
>>
>> Invocation is also relative to that so if you were to execute the class
>> it would be programs/nick/levenshtein/MyClass.class and if the
classpath
>> has /JavaSrc in it, it would be one of the folders that would be
checked
>> for the path/class combination that your package declaration/Class name
>> determines. So in the invocation of
>> programs/nick/levenshtein/MyClass.class the classpath of /JavaSrc would
>> allow /programs/nick/levenshtein/MyClass.class to be found (remember?
>> You compiled into /JavaSrc/programs/nick/levenshtein/MyClass.class)
>>
>> So either remove any package declaration OR make sure that you have the
>> class in a folder that is a combination of a classpath folder plus your
>> package name (in a folder of the same structure with "/" in place of
the
>> "." in the package name)
>>
>> Hope this will help a bit more.
>>
>> Pete
>>
>>
>>
>> Nick Arndt wrote:
>> >>> Scott I have changed my prototype to this:
>>> d Levenshtein pr o extproc(*java:
>>> d 'Difference':
>>> d *constructor)
>>>
>>> d LD pr 10i 0 extproc(*java:
>>> d 'Difference':
>>> d 'LD')
>>> d iString1 like(String1)
>>> d iString2 like(String1)
>>>
>>> and moved my Difference.class to a new directory '/JavaSrc', and added
>>> >> that
>> >>> directory to my classpath.
>>>
>>> But I am still getting a noClassDef found error.
>>>
>>> Any Idea?
>>>
>>> Thanks.
>>>
>>> On Wed, Oct 29, 2008 at 12:48 PM, Scott Klement
>>> <rpg400-l@xxxxxxxxxxxxxxxx>wrote:
>>>
>>>
>>> >>>> Hi Nick,
>>>>
>>>> /QIBM/UserData/Java400/ext is the Java "extensions" directory. It's
>>>> supposed to be used for extensions to the Java language, not for your
>>>> own code.
>>>>
>>>> It's not the "default directory of your CLASSPATH" because it's not
part
>>>> of your CLASSPATH. Indeed, the files in that directory are loaded
>>>> before the CLASSPATH is even considered.
>>>>
>>>> One of the biggest problems with using the extensions directory is
that
>>>> any code in that directory is loaded automatically for every Java
>>>> program. That means you can never have two versions (such as test &
>>>> production versions) running on the same system, because the stuff in
>>>> the ext directory is *always* loaded first.
>>>>
>>>> My recommendation is that you remove it from the ext directory.
>>>> Instead, create your own directory. Maybe with something like this:
>>>>
>>>> CRTDIR ('/java')
>>>> CRTDIR ('/java/publicclasses')
>>>>
>>>> Put all of your classes you want to be available to everyone into
that
>>>> directory, and then set the CLASSPATH envvar to point to that
directory.
>>>>
>>>> ADDENVVAR ENVVAR(CLASSPATH) VALUE('/java/publicclasses')
>>>>
>>>> That's just a suggestion though. The reason your example doesn't
work
>>>> is that it's expecting the Difference class to be in a subdirectory
>>>> named "levenshtein". So for every directory in yoru CLASSPATH, it's
>>>> looking for a subdirectory named levenshtein that contains a
Difference
>>>> class.
>>>>
>>>> In the above example, if the CLASSPATH is /java/publicclasses then
your
>>>> code is looking for a file in the IFS named
>>>> /java/publicclasses/levenshtein/Difference.class -- because of the
way
>>>> you coded it, it's looking for a levenshtein/Difference.class in all
of
>>>> your CLASSPATH directories.
>>>>
>>>>
>>>> Nick Arndt wrote:
>>>>
>>>> >>>>> Hi all I have a need to call a java program from RPG. Here is my
>>>>> prototypes:
>>>>>
>>>>> d Levenshtein pr o extproc(*java:
>>>>> d
>>>>>
>>>>> >>>> 'levenshtein.Difference':
>>>>
>>>> >>>>> d *constructor)
>>>>>
>>>>> d LD pr 10i 0 extproc(*java:
>>>>> d
>>>>> 'levenshtein.Difference':
>>>>> d 'LD')
>>>>> d iString1 like(String1)
>>>>> d iString2 like(String1)
>>>>> d Class s o class(*java:
>>>>> d 'levenshtein.Difference')
>>>>> d String1 s o
>>>>>
>>>>> >>>> CLASS(*JAVA:'java.lang.String')
>>>>
>>>> >>>>> /free
>>>>>
>>>>> // constructor for java class
>>>>> Class = Levenshtein();
>>>>>
>>>>> When I try to call the above constructor I get an RNX0301
>>>>> >> NoClassDefFound
>> >>>>> Here is my java program:
>>>>> The Program is in a Jar file located in QIBM\UserData\Java400\ext
>>>>> Is this the default directory for the classpath var or do i have to
>>>>>
>>>>> >>>> change
>>>>
>>>> >>>>> it to look here?
>>>>>
>>>>> package levenshtein;
>>>>>
>>>>>
>>>>> public class Difference {
>>>>> //*****************************
>>>>> // Compute Levenshtein distance
>>>>> //*****************************
>>>>>
>>>>> public int LD (String s, String t) {
>>>>> int d[][]; // matrix
>>>>> int n; // length of s
>>>>> int m; // length of t
>>>>> int i; // iterates through s
>>>>> int j; // iterates through t
>>>>> char s_i; // ith character of s
>>>>> char t_j; // jth character of t
>>>>> int cost; // cost
>>>>>
>>>>> // Step 1
>>>>>
>>>>> n = s.length ();
>>>>> m = t.length ();
>>>>> if (n == 0) {
>>>>> return m;
>>>>> }
>>>>> if (m == 0) {
>>>>> return n;
>>>>> }
>>>>> d = new int[n+1][m+1];
>>>>>
>>>>> // Step 2
>>>>>
>>>>> for (i = 0; i <= n; i++) {
>>>>> d[i][0] = i;
>>>>> }
>>>>> for (j = 0; j <= m; j++) {
>>>>> d[0][j] = j;
>>>>> }
>>>>> // Step 3
>>>>> for (i = 1; i <= n; i++) {
>>>>> s_i = s.charAt (i - 1);
>>>>> // Step 4
>>>>> for (j = 1; j <= m; j++) {
>>>>> t_j = t.charAt (j - 1);
>>>>>
>>>>> // Step 5
>>>>>
>>>>> if (s_i == t_j) {
>>>>> cost = 0;
>>>>> }
>>>>> else {
>>>>> cost = 1;
>>>>> }
>>>>> // Step 6
>>>>>
>>>>> d[i][j] = Minimum (d[i-1][j]+1, d[i][j-1]+1,
>>>>> >> d[i-1][j-1]
>> >>>> +
>>>>
>>>> >>>>> cost);
>>>>>
>>>>> }
>>>>>
>>>>> }
>>>>>
>>>>> // Step 7
>>>>>
>>>>> return d[n][m];
>>>>>
>>>>> }
>>>>>
>>>>>
>>>>> // get minimum of three values
>>>>> private int Minimum (int a, int b, int c) {
>>>>> int mi;
>>>>>
>>>>> mi = a;
>>>>> if (b < mi) {
>>>>> mi = b;
>>>>> }
>>>>> if (c < mi) {
>>>>> mi = c;
>>>>> }
>>>>> return mi;
>>>>> }
>>>>> }
>>>>>
>>>>> >>>> --
>>>> This is the RPG programming on the AS400 / iSeries (RPG400-L) mailing
>>>> >> list
>> >>>> To post a message email: RPG400-L@xxxxxxxxxxxx
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>>>> visit: http://lists.midrange.com/mailman/listinfo/rpg400-l
>>>> or email: RPG400-L-request@xxxxxxxxxxxx
>>>> Before posting, please take a moment to review the archives
>>>> at http://archive.midrange.com/rpg400-l.
>>>>
>>>>
>>>>
>>>> >> --
>> This is the RPG programming on the AS400 / iSeries (RPG400-L) mailing
list
>> To post a message email: RPG400-L@xxxxxxxxxxxx
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>> visit: http://lists.midrange.com/mailman/listinfo/rpg400-l
>> or email: RPG400-L-request@xxxxxxxxxxxx
>> Before posting, please take a moment to review the archives
>> at http://archive.midrange.com/rpg400-l.
>>
>>
>> --
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