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Oracle objects and collections with Java

lewiscSep 15 2013 — edited Oct 15 2014

Hi.

I've designed a lot of database applications in my time. I pretty much always make heavy use of objects (oracle database defined, complex types - also collections) for parameters and such to procedures. I've never had any problem with it in the past (8i, 9i, 10g or 11). I made some suggestions for improvements at my current gig and got some fear and doubt coming back at me.

I've used objects with both Java and .Net with no issue but I was not the one doing the middle tier coding. So, I don't really know how to respond to this. I can do Java coding but am nowhere near knowledgeable on connection pooling.

Specifically, the reason that the dev team does not want to do this is because, and I quote:

Java mapping for oracle type and table type is oracle.sql.STRUCT. When oracle.sql.STRUCT is used then vendor connection needs to be used. Vendor connection is not logical connection it is physical connection. So whenever we close the connection that connection gets destroyed and connection pool will create new connection.

So, the fear is that this will cause a performance issue if every call has to reconnect to the database. I *know* this *can* work without performance issues. Is there a particular thing to look at? Type Map vs Struct? Pool configuration? Something else?

This Tomcat (and Mule) on 11g.Linux is the OS. We're using the latest Oracle drivers.

Thanks in advance for any insight.

LewisC

This post has been answered by dsurber-Oracle on Oct 2 2013

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843834

I agree with your hunch. The parser should treat dlmd:record as just another element (colons are allowed in XML element names when namspace feature is turned off). Maybe you could elaborate a bit on what parser you're using, what Document (JDOM or DOM) you're building and where the exception comes from (io exception is kind of strange, too).

843834

Hi
I am using JAXP 1.1 and I am builidng a DOM document. The exception I get is a SAX Exception and the following is the stack trace

java.lang.NullPointerException
at org.apache.crimson.parser.Parser2.parseInternal(Parser2.java:523)
at org.apache.crimson.parser.Parser2.parse(Parser2.java:304)
at org.apache.crimson.parser.XMLReaderImpl.parse(XMLReaderImpl.java:433)
at org.apache.crimson.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:179)

at javax.xml.parsers.DocumentBuilder.parse(DocumentBuilder.java:161)
at dlnet.DLXMLParse.dlDocumentBuild(DLXMLParse.java:282)
at dlnet.DLXMLParse.dlStart_Parse(DLXMLParse.java:50)
at dlnet.DLTrigger.main(DLTrigger.java:40)

Hope you can suggest a solution.....

843834

I see. I only tried xerces with your example and it was just fine. You're using Crimson, though and there seems to be a bug in crimson1.1. Go, get crimson1.1.1 from http://xml.apache.org and it'll parse fine.

Good luck,
Leo.

843834

Using the new version of Crimson does not help either. After I build the new Document Factory I set the namespace awareness to false and yet it gives me a sax exception......Could something else be wrong too!??

Thanks for your help....
Prashanth

843834

Prashanth,
this is what I'm doing. First, the parser test code:

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;

public class JAXPDOMTest {

    public void domParse(String url) {
        DocumentBuilder parser;
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        factory.setValidating(false);
        factory.setNamespaceAware(false);

        try {
            parser = factory.newDocumentBuilder();
            Document doc = parser.parse(url);

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    static public void main(String[] args)
    {
       JAXPDOMTest x=new JAXPDOMTest();
       x.domParse("test.xml");
    }
}

and here's test.xml:

<?xml version="1.0"?>

<metadata>
   <schema>Schema 1</schema>
   <schemaversion>DX:MD1.0 S:1.0</schemaversion>
   <dlmd:record>Record</dlmd:record>
</metadata>

jaxp-1.1 is my directory containing the official 1.1 release and my complete classpath look like this:
CLASSPATH=d:\xml_tools\jaxp-1.1\crimson.jar;d:\xml_tools\jaxp-1.1\jaxp.jar;.

I run the above (java JAXPDOMTest), I get:
java.lang.NullPointerException
at org.apache.crimson.parser.Parser2.parseInternal(Parser2.java:523)
at org.apache.crimson.parser.Parser2.parse(Parser2.java:304)
at org.apache.crimson.parser.XMLReaderImpl.parse(XMLReaderImpl.java:433)

at org.apache.crimson.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:179)
at javax.xml.parsers.DocumentBuilder.parse(DocumentBuilder.java:134)
at JAXPDOMTest.domParse(JAXPDOMTest.java:15)
at JAXPDOMTest.main(JAXPDOMTest.java:24)

I set the class path to:
CLASSPATH=d:\xml_tools\crimson-1.1.1\crimson.jar;d:\xml_tools\crimson-1.1.1\jaxp.jar;.

and, voila, no exception.

Hope that helps,
Leo.

843834

Hi

This is what I did just now....I created a file out of the pseudo string and passed it to be parsed with crimson.....it gives me an error irrespective of whether I turn Namespace awareness true or not!

What could the reason be?

Thanks
Prashanth

843834

Well, that seems to be classic dilemma. The same code works fine on my machine, but has trouble on yours. I'm running on 95 with JSDK 1.3 (build 1.3.0-C).
I'm afraid I can't help you any further, since I can't reproduce this behaviour.

Leo.

843834

Thanks anyways....guess I have to figure it out myself.
Prashanth

843834

It finally worked!!!! This is what I did. I had to delete the jar files in the \lib\ext directory of Java Runtime Environment and it started working. Thanks Leo you have been of great help.......

Prashanth

843834

Yeah, that's a valuable lesson. jar files in lib/ext, I believe, are accessed before stuff in the class path. Glad to hear it's working.

843834

P.S.
check out http://forums.java.sun.com/rewardFaq.jsp#assign

;-)

843834

Yup! I did....It would be helpful if yo could throw some light one one other question i've posted!

http://forum.java.sun.com/thread.jsp?forum=34&thread=150639

Thanks

843834

Thx for the DDs. I saw this question before, but haven't done anything like this and I'm afraid, I can't give you advice on that one, but my instincts tell me, you'd be better off with the database solution.

Good luck.

843834

Thanks for the info.
I had the same problem, I have it no more

Small note: I had to put the XALAN.jar file AFTER the crimson.jar and jaxp.jar in order to make it work.

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#11g, #connection, #database-connectivity-discussions, #java, #jdbc

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Java Database Connectivity (JDBC)

Oracle objects and collections with Java

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