CODEWITHSUNDEEP
javaweb-services
Meastro
Meastro

Reputation: 81

jaxb unable to create an instance of abstract class

@XmlSeeAlso({ Dog.class, Cat.class })
public abstract class Animal {}

@XmlRootElement(name="dog")
public class Dog extends Animal {}

@XmlRootElement(name="cat")
public class Cat extends Animal {}

@WebService(name = "WebServiceDemo", serviceName = "WebServiceDemo")
@SOAPBinding(style = SOAPBinding.Style.DOCUMENT, use = SOAPBinding.Use.LITERAL,
            parameterStyle = SOAPBinding.ParameterStyle.WRAPPED)
public class WebServiceDemo {

@WebMethod
public String service(@WebParam(name = "animal") Animal animal) {
       System.out.println("animal service calling.....");
       return animal;
}
}

Now when i am calling this service method from client with Animal calss as a parameter that time i am getting error-

Caused by: javax.xml.bind.UnmarshalException: Unable to create an instance of Animal - with linked exception: [java.lang.InstantiationException] at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallingContext.handleEvent(UnmarshallingContext.java:616) at com.sun.xml.bind.v2.runtime.unmarshaller.Loader.reportError(Loader.java:244) at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallingContext.createInstance(UnmarshallingContext.java:583) at com.sun.xml.bind.v2.runtime.unmarshaller.StructureLoader.startElement(StructureLoader.java:181) at com.sun.xml.bind.v2.runtime.unmarshaller.XsiTypeLoader.startElement(XsiTypeLoader.java:73) at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallingContext._startElement(UnmarshallingContext.java:455) at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallingContext.startElement(UnmarshallingContext.java:433) at com.sun.xml.bind.v2.runtime.unmarshaller.InterningXmlVisitor.startElement(InterningXmlVisitor.java:71) at com.sun.xml.bind.v2.runtime.unmarshaller.SAXConnector.startElement(SAXConnector.java:137) at com.sun.xml.bind.unmarshaller.DOMScanner.visit(DOMScanner.java:240) at com.sun.xml.bind.unmarshaller.DOMScanner.visit(DOMScanner.java:277) at com.sun.xml.bind.unmarshaller.DOMScanner.visit(DOMScanner.java:246) at com.sun.xml.bind.unmarshaller.DOMScanner.scan(DOMScanner.java:123) at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal0(UnmarshallerImpl.java:314) at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal(UnmarshallerImpl.java:293) at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal(UnmarshallerImpl.java:244) at org.jboss.ws.core.jaxws.JAXBDeserializer.deserialize(JAXBDeserializer.java:71)

Upvotes: 2

Views: 9299

Answers (1)

Juned Ahsan
Juned Ahsan

Reputation: 68715

Abstract classes cannot be instantiated, that is the basic rule for them in Java. From the javadocs:

An abstract class is a class that is declared abstract—it may or may not include abstract methods. Abstract classes cannot be instantiated, but they can be subclassed.

Jaxb internally will try to unmarshall your xml to the java object. But if it is not able to create an object of Animal, how will it work. Hence it throws the exception. You need to provide a non-abstract class to JaxB to work.

Upvotes: 2

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