Use of inheritance....

hi friends we are all say inheritance is one of the important concept in oops that will support ed by java,it will reduce the code length but in real world programming most of the cases we dont use inheritance concepts for user defined classes... My doubt is why we dont use
inheritance is real time programming...?

hi friends we are all say inheritance is one of the
important concept in oops that will support ed by
java, it will reduce the code length but in real worldI agree with the people here when they disagree with you on this.
programming most of the cases we dont use inheritance
concepts for user defined classes... Interesting. I thought every user-defined class is derived from Object. Besides that, maybe we often don't extend random classes all the time because we understand the OO design principles...
My doubt is why
we dont use
inheritance is real time programming...?I assume it's because most real-time programs are written in C or other structured languages. But I'm sure there are exceptions.

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    </Trajecten>My domain model corresponts to the XSD, so there is a Traject object and an inherited SpecialTraject object.
    In the mapping I used the Advanced properties->inheritance on both descriptors telling the Traject descriptor that it was the 'Root Parent Descriptor' ('Use class indicator field' -> 'use XML Schema Type attribute', 'Use class indicator dictionary') and the SpecialTraject what it Child Descriptor was ('Traject').
    When I test my mapping it always results in the same error (no matter how I configure this inheritance mapping). It says :
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    Descriptor: XMLDescriptor(Traject --> [])What am I doing wrong? Does anybody know a sollution?
    Best regards,
    Jouke Stoel
    Developer

    This is the changed XML descriptor file. When I deploy the file it automaticly overrides the old file so it ain't possible that I was still using the wrong file
    <toplink:class-indicator-mappings>
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            <toplink:class-indicator xsi:type="xsd:string">SpecialTraject</toplink:class-indicator>
        </toplink:class-indicator-mapping>
    </toplink:class-indicator-mappings>I have posted the stacktrace but I had to translate a bit because my exception was in Dutch :)
    Locale is a great invention
    Exception [TOPLINK-44] (Oracle TopLink - 10g Release 3 (10.1.3.1.0) (Build 061004)): oracle.toplink.exceptions.DescriptorException
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         at oracle.toplink.exceptions.DescriptorException.missingClassIndicatorField(DescriptorException.java:887)
         at oracle.toplink.internal.ox.QNameInheritancePolicy.classFromRow(QNameInheritancePolicy.java:84)
         at oracle.toplink.internal.ox.XMLRelationshipMappingNodeValue.processChild(XMLRelationshipMappingNodeValue.java:13)
         at oracle.toplink.internal.ox.XMLCompositeCollectionMappingNodeValue.startElement(XMLCompositeCollectionMappingNodeValue.java:62)
         at oracle.toplink.ox.record.UnmarshalRecord.startElement(UnmarshalRecord.java:352)
         at oracle.xml.parser.v2.NonValidatingParser.parseElement(NonValidatingParser.java:1288)
         at oracle.xml.parser.v2.NonValidatingParser.parseRootElement(NonValidatingParser.java:336)
         at oracle.xml.parser.v2.NonValidatingParser.parseDocument(NonValidatingParser.java:303)
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         at oracle.toplink.internal.ox.record.SAXUnmarshaller.unmarshal(SAXUnmarshaller.java:147)
         at oracle.toplink.ox.XMLUnmarshaller.unmarshal(XMLUnmarshaller.java:228)
    .

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