java - JAXB: Can't unmarshal JAXBElement<?>, getting ElementNSImpl instead -

related jaxb: how implement jaxb-compatible variant wrapper class?, tried use jaxbelement represent "variant" or "any-type".

marshalling went fine, during unmarshalling, jaxb tries assign elementnsimpl jaxbelement field.

test code

(copy+paste+run)

import static java.lang.system.*; import java.io.*; import java.util.*;  import javax.xml.bind.*; import javax.xml.bind.annotation.*; import javax.xml.namespace.*;  import org.junit.*;  public class _jaxbelementproblem {      @xmlrootelement     @xmltype     @xmlaccessortype(xmlaccesstype.none)     static class myobject {          public static final qname variant_name = new qname("qqq");          @xmlanyelement(lax = true)         private jaxbelement<object> single = null;         @xmlelementwrapper(name = "elements")         @xmlanyelement(lax = true)         final list<jaxbelement<object>> elements =                 new linkedlist<jaxbelement<object>>();          @suppresswarnings("unused")         private myobject() {         }          public myobject(object o) {             single = new jaxbelement<object>(variant_name, object.class, o);         }          public object getsingle() {             return single.getvalue();         }          public list<object> getelements() {             list<object> ret = new linkedlist<object>();              (jaxbelement<?> e : elements) {                 ret.add(e.getvalue());             }              return ret;         }          @override         public string tostring() {             return "myobject (single=" + single.getvalue() + "; elements: "                     + getelements() + ")";         }      }      private static final jaxbcontext c;     private static final marshaller m;     private static final unmarshaller u;      static {         try {             c = jaxbcontext.newinstance(myobject.class);              m = c.createmarshaller();             u = c.createunmarshaller();              m.setproperty(marshaller.jaxb_formatted_output, boolean.true);         } catch (jaxbexception ex) {             throw new error(ex);         }     }      private void testmarshalunmarshal(object root) throws exception {         out.println("\nmarshalled - - - - - - - - - - - - - - - - - - - -");         stringwriter sw = new stringwriter();         m.marshal(root, sw);         out.println(sw.tostring() + "\n");          out.println("\nunmarshalled - - - - - - - - - - - - - - - - - - - -");         object reunmarshalled = u.unmarshal(new stringreader(sw.tostring()));         out.println(reunmarshalled + "\n");     }      @before     public void before() {         out.println("\n= = = = = = = = = = = = = = = = = = = =");     }      @test     public void test1() throws exception {         myobject root = new myobject(integer.valueof(12345));         testmarshalunmarshal(root);     }      @test     public void test2() throws exception {         myobject sub = new myobject(integer.valueof(12345));         myobject root = new myobject(sub);         testmarshalunmarshal(root);     }      @test     public void test3() throws exception {         myobject osub = new myobject(integer.valueof(12345));         list<myobject> osubs =                 arrays.aslist(new myobject("sub-1"), new myobject("sub-2"),                         new myobject("sub-3"));          myobject root = new myobject(osub);         (myobject o : osubs) {             root.elements.add(new jaxbelement<object>(myobject.variant_name,                     object.class, o));         }          testmarshalunmarshal(root);     } } 

test output

(as can see, unmarshalling doesn't take place)

= = = = = = = = = = = = = = = = = = = =  marshalled - - - - - - - - - - - - - - - - - - - - <?xml version="1.0" encoding="utf-8" standalone="yes"?> <myobject>     <qqq xsi:type="xs:int" xmlns:xs="http://www.w3.org/2001/xmlschema" xmlns:xsi="http://www.w3.org/2001/xmlschema-instance">12345</qqq>     <elements/> </myobject>    unmarshalled - - - - - - - - - - - - - - - - - - - -  = = = = = = = = = = = = = = = = = = = =  marshalled - - - - - - - - - - - - - - - - - - - - <?xml version="1.0" encoding="utf-8" standalone="yes"?> <myobject>     <qqq xsi:type="myobject" xmlns:xsi="http://www.w3.org/2001/xmlschema-instance">         <qqq xsi:type="xs:int" xmlns:xs="http://www.w3.org/2001/xmlschema">12345</qqq>         <elements/>     </qqq>     <elements/> </myobject>    unmarshalled - - - - - - - - - - - - - - - - - - - -  = = = = = = = = = = = = = = = = = = = =  marshalled - - - - - - - - - - - - - - - - - - - - <?xml version="1.0" encoding="utf-8" standalone="yes"?> <myobject>     <qqq xsi:type="myobject" xmlns:xsi="http://www.w3.org/2001/xmlschema-instance">         <qqq xsi:type="xs:int" xmlns:xs="http://www.w3.org/2001/xmlschema">12345</qqq>         <elements/>     </qqq>     <elements>         <qqq xsi:type="myobject" xmlns:xsi="http://www.w3.org/2001/xmlschema-instance">             <qqq xsi:type="xs:string" xmlns:xs="http://www.w3.org/2001/xmlschema">sub-1</qqq>             <elements/>         </qqq>         <qqq xsi:type="myobject" xmlns:xsi="http://www.w3.org/2001/xmlschema-instance">             <qqq xsi:type="xs:string" xmlns:xs="http://www.w3.org/2001/xmlschema">sub-2</qqq>             <elements/>         </qqq>         <qqq xsi:type="myobject" xmlns:xsi="http://www.w3.org/2001/xmlschema-instance">             <qqq xsi:type="xs:string" xmlns:xs="http://www.w3.org/2001/xmlschema">sub-3</qqq>             <elements/>         </qqq>     </elements> </myobject>    unmarshalled - - - - - - - - - - - - - - - - - - - - 

unmarshalling exceptions

java.lang.illegalargumentexception: can not set javax.xml.bind.jaxbelement field my._jaxbelementproblem$myobject.single com.sun.org.apache.xerces.internal.dom.elementnsimpl @ sun.reflect.unsafefieldaccessorimpl.throwsetillegalargumentexception(unsafefieldaccessorimpl.java:146) @ sun.reflect.unsafefieldaccessorimpl.throwsetillegalargumentexception(unsafefieldaccessorimpl.java:150) @ sun.reflect.unsafeobjectfieldaccessorimpl.set(unsafeobjectfieldaccessorimpl.java:63) @ java.lang.reflect.field.set(field.java:657) @ com.sun.xml.internal.bind.v2.runtime.reflect.accessor$fieldreflection.set(accessor.java:234) @ com.sun.xml.internal.bind.v2.runtime.reflect.accessor.receive(accessor.java:160) @ com.sun.xml.internal.bind.v2.runtime.unmarshaller.unmarshallingcontext.endelement(unmarshallingcontext.java:507) @ com.sun.xml.internal.bind.v2.runtime.unmarshaller.saxconnector.endelement(saxconnector.java:145) @ com.sun.org.apache.xerces.internal.parsers.abstractsaxparser.endelement(abstractsaxparser.java:601) @ com.sun.org.apache.xerces.internal.impl.xmldocumentfragmentscannerimpl.scanendelement(xmldocumentfragmentscannerimpl.java:1782) @ com.sun.org.apache.xerces.internal.impl.xmldocumentfragmentscannerimpl$fragmentcontentdriver.next(xmldocumentfragmentscannerimpl.java:2938) @ com.sun.org.apache.xerces.internal.impl.xmldocumentscannerimpl.next(xmldocumentscannerimpl.java:648) @ com.sun.org.apache.xerces.internal.impl.xmlnsdocumentscannerimpl.next(xmlnsdocumentscannerimpl.java:140) @ com.sun.org.apache.xerces.internal.impl.xmldocumentfragmentscannerimpl.scandocument(xmldocumentfragmentscannerimpl.java:511) @ com.sun.org.apache.xerces.internal.parsers.xml11configuration.parse(xml11configuration.java:808) @ com.sun.org.apache.xerces.internal.parsers.xml11configuration.parse(xml11configuration.java:737) @ com.sun.org.apache.xerces.internal.parsers.xmlparser.parse(xmlparser.java:119) @ com.sun.org.apache.xerces.internal.parsers.abstractsaxparser.parse(abstractsaxparser.java:1205) @ com.sun.org.apache.xerces.internal.jaxp.saxparserimpl$jaxpsaxparser.parse(saxparserimpl.java:522) @ com.sun.xml.internal.bind.v2.runtime.unmarshaller.unmarshallerimpl.unmarshal0(unmarshallerimpl.java:200) @ com.sun.xml.internal.bind.v2.runtime.unmarshaller.unmarshallerimpl.unmarshal(unmarshallerimpl.java:173) @ javax.xml.bind.helpers.abstractunmarshallerimpl.unmarshal(abstractunmarshallerimpl.java:137) @ javax.xml.bind.helpers.abstractunmarshallerimpl.unmarshal(abstractunmarshallerimpl.java:194) @ my._jaxbelementproblem.testmarshalunmarshal(_jaxbelementproblem.java:84) @ my._jaxbelementproblem.test3(_jaxbelementproblem.java:119) 

running example:

(hint: jaxbhelper utils-apl-derived, short forms of unmarshalling , marshalling routines)

import static org.junit.assert.assertequals;  import java.util.arrays; import java.util.list;  import javax.xml.bind.annotation.xmlaccesstype; import javax.xml.bind.annotation.xmlaccessortype; import javax.xml.bind.annotation.xmlelement; import javax.xml.bind.annotation.xmlelements; import javax.xml.bind.annotation.xmlrootelement; import javax.xml.bind.annotation.xmltype;  import org.junit.test; import org.omnaest.utils.xml.jaxbxmlhelper;  public class jaxbanyelementtest {   @xmltype   @xmlaccessortype(xmlaccesstype.field)   protected static class testsubentity   {     /* ********************************************** variables ********************************************** */     @xmlelement     private string fieldstring  = null;     @xmlelement     private int    fieldinteger = -1;      /* ********************************************** methods ********************************************** */      /**      * @see testsubentity      */     public testsubentity()     {       super();     }      /**      * @see testsubentity      * @param fieldstring      * @param fieldinteger      */     public testsubentity( string fieldstring, int fieldinteger )     {       super();       this.fieldstring = fieldstring;       this.fieldinteger = fieldinteger;     }      /**      * @return fieldstring      */     public string getfieldstring()     {       return this.fieldstring;     }      /**      * @param fieldstring      *          fieldstring set      */     public void setfieldstring( string fieldstring )     {       this.fieldstring = fieldstring;     }      /**      * @return fieldinteger      */     public int getfieldinteger()     {       return this.fieldinteger;     }      /**      * @param fieldinteger      *          fieldinteger set      */     public void setfieldinteger( int fieldinteger )     {       this.fieldinteger = fieldinteger;     }      @override     public int hashcode()     {       final int prime = 31;       int result = 1;       result = prime * result + this.fieldinteger;       result = prime * result + ( ( this.fieldstring == null ) ? 0 : this.fieldstring.hashcode() );       return result;     }      @override     public boolean equals( object obj )     {       if ( == obj )       {         return true;       }       if ( obj == null )       {         return false;       }       if ( !( obj instanceof testsubentity ) )       {         return false;       }       testsubentity other = (testsubentity) obj;       if ( this.fieldinteger != other.fieldinteger )       {         return false;       }       if ( this.fieldstring == null )       {         if ( other.fieldstring != null )         {           return false;         }       }       else if ( !this.fieldstring.equals( other.fieldstring ) )       {         return false;       }       return true;     }    }    @xmlrootelement   @xmlaccessortype(xmlaccesstype.field)   protected static class testentity   {     @xmlelements({ @xmlelement(name = "int", type = integer.class), @xmlelement(name = "string", type = string.class),         @xmlelement(name = "testsubentity", type = testsubentity.class), @xmlelement(name = "other") })     private list<object> anyelementlist = null;      /**      * @return anyelementlist      */     public list<object> getanyelementlist()     {       return this.anyelementlist;     }      /**      * @param anyelementlist      *          anyelementlist set      */     public void setanyelementlist( list<object> anyelementlist )     {       this.anyelementlist = anyelementlist;     }      /* (non-javadoc)      * @see java.lang.object#hashcode()      */     @override     public int hashcode()     {       final int prime = 31;       int result = 1;       result = prime * result + ( ( this.anyelementlist == null ) ? 0 : this.anyelementlist.hashcode() );       return result;     }      /* (non-javadoc)      * @see java.lang.object#equals(java.lang.object)      */     @override     public boolean equals( object obj )     {       if ( == obj )       {         return true;       }       if ( obj == null )       {         return false;       }       if ( !( obj instanceof testentity ) )       {         return false;       }       testentity other = (testentity) obj;       if ( this.anyelementlist == null )       {         if ( other.anyelementlist != null )         {           return false;         }       }       else if ( !this.anyelementlist.equals( other.anyelementlist ) )       {         return false;       }       return true;     }    }    @suppresswarnings("cast")   @test   public void test()   {     //     final testentity testentity = new testentity();      //     final list<object> anyelementlist = arrays.aslist( (object) "a", integer.valueof( 1 ), boolean.valueof( true ),                                                        new testsubentity( "field1", 1 ) );     testentity.setanyelementlist( anyelementlist );      //     final string objectasxml = jaxbxmlhelper.storeobjectasxml( testentity );     system.out.println( objectasxml );      //     final testentity objectfromxml = jaxbxmlhelper.loadobjectfromxml( objectasxml, testentity.class );     assertequals( testentity, objectfromxml );   } } 

output:

<?xml version="1.0" encoding="utf-8" standalone="yes"?> <testentity>     <string>a</string>     <int>1</int>     <other xsi:type="xs:boolean" xmlns:xs="http://www.w3.org/2001/xmlschema" xmlns:xsi="http://www.w3.org/2001/xmlschema-instance">true</other>     <testsubentity>         <fieldstring>field1</fieldstring>         <fieldinteger>1</fieldinteger>     </testsubentity> </testentity>