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Question

Confusion over class resolution in Oracle java stored procedures

Answer 1

+1 A:

Do this:

try
{
    System.out.println("Class.forName returned: " + 
        Class.forName("com.sun.xml.messaging.saaj.soap.MessageFactoryImpl"));
}
catch(final Throwable ex)
{
    ex.printStackTrace();
    System.exit(1);
}

Just to be 100and10% sure that it is not throwing an exception that is somehow being hidden and that it is really returning null. If it is still the case please let me know (interesting problem if the code above works, but returns null).

TofuBeer 2009-02-28 02:22:47

Sheesh. My mistake. The Class.forName("com.sun.yada.yada..") line throws an exception: java.lang.ClassNotFoundException: com/sun/xml/messaging/saaj/soap/MessageFactoryImpl

Chris Farmer 2009-03-02 15:06:18

Answer 2

+4 A:

First of all, verify outside of Oracle that the class you are looking for is actually in that jar file. I expect it is, but it doesn't hurt to check.

Then, I would check what classes have been loaded and whether they have valid statuses.

SELECT object_name, dbms_java.longname(object_name), status
  FROM user_objects
  WHERE object_type='JAVA CLASS'
  ORDER BY 1

You might want to limit this somewhat if there are a lot of classes, e.g.:

WHERE dbms_java.longname(object_name) LIKE '%MessageFactoryImpl'

If the class is not there, or it is there with the wrong package name, then the problem is with the loadjava command.

If the class is there but its status is INVALID, then check USER_ERRORS to see what the errors are. I don't recall if I've done dynamic class loading within Oracle, but I recall that static linking would give errors that implied a class didn't exist when it really existed but had errors.

New info after loadjava output posted

The loadjava output seems inconsistent with your attempt to find the class in the database. If it is being loaded but not resolved, it should still be listed, but with an INVALID status.

I got the JAR and tried it myself in an empty schema. The class loads but is invalid as expected:

dev> select object_name, dbms_java.longname(object_name),status
  2  from user_objects
  3  where object_name like '%MessageFactoryImpl';

OBJECT_NAME
--------------------------------------------------------------------------------
DBMS_JAVA.LONGNAME(OBJECT_NAME)
--------------------------------------------------------------------------------
STATUS
-------
/3e484eb0_MessageFactoryImpl
com/sun/xml/messaging/saaj/soap/MessageFactoryImpl
INVALID

I then checked what the error were on the class:

dev> alter java class "com/sun/xml/messaging/saaj/soap/MessageFactoryImpl" resolve;
dev> /

Warning: Java altered with compilation errors.

dev> show error
Errors for JAVA CLASS "/3e484eb0_MessageFactoryImpl":

LINE/COL ERROR
-------- -----------------------------------------------------------------
0/0      ORA-29521: referenced name javax/xml/soap/MessageFactory could
         not be found

0/0      ORA-29521: referenced name javax/xml/soap/SOAPMessage could not
         be found

0/0      ORA-29521: referenced name javax/xml/soap/MimeHeaders could not
         be found

0/0      ORA-29521: referenced name javax/xml/soap/SOAPException could not
         be found

(These errors would also be listed in USER_ERRORS, assuming resolution was attempted at least once.)

So clearly this class references classes from the base SOAP library. You would have to load that too -- have you done that?

FYI, when I write some code to do the Class.forName() call, I do get the ClassNotFoundException. Which may seem counter-intuitive since the class object does exist in the schema. However, an invalid class doesn't really "exist" from the point of view of the class loader in Oracle; and in order for the class to be valid Oracle has to be able to resolve all of its references to other classes.

Dave Costa 2009-03-02 16:22:19

The saaj-impl.jar file does indeed contain the com.sun.xml.messaging.saaj.soap.MessageFactoryImpl class.Thanks for the use of the "longname" function. I couldn't figure out how to get those full names back! There are no longname classes that are LIKE '%MessageFactory%' in my Oracle instance.

Chris Farmer 2009-03-02 21:02:11

So, it looks pretty clear that loadjava isn't doing what I want it to do. Do you have any ideas how I can debug my use of that?

Chris Farmer 2009-03-02 21:18:33

I would expect that the verbose output from loadjava would contain at least some indication. Can you post a representative sample of the output?

Dave Costa 2009-03-02 21:28:22

Thanks. I edited my post to contain the verbose loadjava output.

Chris Farmer 2009-03-02 22:17:25

Edited answer. My best guess at this point is that you haven't loaded other jars that contain classes referenced by the SAAJ classes.

Dave Costa 2009-03-03 18:08:42

Nice investigation

stjohnroe 2009-03-09 13:36:04

Answer 3

A:

Try # 3 :-) (I don't use Oracle... but this is a neat problem to debug...)

Does the info here on Class.forName in Oracle help?

http://download.oracle.com/docs/cd/B14117_01/java.101/b12021/appover.htm#i1006547

This presents as a ClassLoader issue, so hoepfully the solution is along the same lines as what happens in the "real, non-Oracle" world :-)

Edit... another try...

Ok looking at it some more... what is the output of the following:

System.out.println("vm vendor:     " + System.getProperty("java.vendor"));
System.out.println("vm version:    " + System.getProperty("java.version"));
System.out.println("class version: " + System.getProperty("java.class.version"));

I am wondering if there is an issue with the class file version - do the class files have a version that cannot be run on the Oracle VM?

TofuBeer 2009-03-02 21:55:26

Yeah, this is my database schema, so I can do whatever I want. The problem is I don't necessarily know what I'm doing!

Chris Farmer 2009-03-02 22:29:25

that make two of us :-)

TofuBeer 2009-03-02 23:11:06

Answer 4

+1 A:

Is this the first time your executing Java on the database? Here is hello world implementation to make sure your Oracle JVM is running properly and you have the necessary permissions. You said "my database schema, so I can do whatever I want" -doesn't mean you have the proper grants.

SQL> create or replace and compile java source named "Hello" as 
   public class Hello{ 
      public static String world() { 
         return "Hello World "; 
      } 
   }; 
/ 

Java created.

Now the wrapper function

SQL> create or replace function Hello RETURN VARCHAR2 
     as LANGUAGE JAVA NAME 'Hello.world() return String'; 
     / 

Function created.

Now test it

SQL> select Hello from dual; 

HELLO 
----------------------------------- 
Hello World

Brian 2009-03-07 02:07:54

Oh, I can run other methods just fine. I tried to say that in my message when I said that I can access the target url via http. That's within my java class running in oracle. It's my hello world.

Chris Farmer 2009-03-07 04:40:43

Answer 5

A:

Class resolution and loading are complex operations handled by the VM. The algorithm to be used by these 2 operations as described in the spec is left open for VM implementors. My feeling is that in your case the resolution works as the operation checks only the availability of the class itself, while it is failing later when trying to effectively load the class (most probably due to missing dependencies: when loading the class, the VM needs to resolve at least all direct references to other classes). You'll have to make sure that all classes are available to Oracle and performing a quick Google search for ORA-29534 shows tons of people having this problem (and I'm pretty sure somebody figured it out).

./alex

alexpopescu 2009-03-08 09:41:51

Answer 6

A:

The saaj-impl.jar is part of the SAAJ component of the Web Services Developer Pack. It has dependencies on other JARs that ship with SAAJ, for instance, it definitely depends on saaj-api.jar and activation.jar, to my knowledge. Of course, saaj-api.jar is bound to depend on a lot of other JARs as well.

As far as JWSDP 1.5 is concerned, you could find the information in JWSDP 1.5 Release Notes to be useful. JWSDP 1.6 has different JARs in SAAJ I havent found the JWSDP 2.0 Release Notes to be particularly useful in this regard. BTW, JWSDP 2.0 would have different JARs to be placed in the classpath; so the scope of your problem eventually depends on the version of saaj-impl.jar that you use.

Just in case you might need it, some documentation is already available on how to load the SOAP client JARs into an Oracle database and to utilize them, in the following pages. I presume these to be different from the SAAJ JARs that comes with your library though.

Vineet Reynolds 2009-03-08 21:42:22

Answer 7

A:

Hi I would like to ask you what appropriate socket permissions need to be granted?

2009-03-11 08:45:30

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Confusion over class resolution in Oracle java stored procedures

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