JAX-WS MarshalException with custom JAX-B bindings: Unable to marshal type "java.lang.String" as an element because it is missing an @XmlRootElement annotation

Question

I seem to be having an issue with Jax-WS and Jax-b playing nicely together. I need to consume a web-service, which has a predefined WSDL. When executing the generated client I am receiving the following error:

javax.xml.ws.WebServiceException: javax.xml.bind.MarshalException - with linked exception: [com.sun.istack.SAXException2: unable to marshal type "java.lang.String" as an element because it is missing an @XmlRootElement annotation]

This started occurring when I used an external custom binding file to map needlessly complex types to java.lang.string. Here is an excerpt from my binding file:

<?xml version="1.0" encoding="UTF-8"?>
  <bindings xmlns="http://java.sun.com/xml/ns/jaxb" version="2.0" 
      xmlns:xs="http://www.w3.org/2001/XMLSchema"
      xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/"
      xmlns:xjc="http://java.sun.com/xml/ns/jaxb/xjc"&gt;
    <bindings schemaLocation="http://localhost:7777/GESOR/services/RegistryUpdatePort?wsdl#types?schema1" node="/xs:schema">
      <bindings node="//xs:element[@name='StwrdCompany']//xs:complexType//xs:sequence//xs:element[@name='company_name']">
        <property>
          <baseType name="java.lang.String" />
        </property>
      </bindings>
      <bindings node="//xs:element[@name='StwrdCompany']//xs:complexType//xs:sequence//xs:element[@name='address1']">
        <property>
          <baseType name="java.lang.String" />
        </property>
      </bindings>
      <bindings node="//xs:element[@name='StwrdCompany']//xs:complexType//xs:sequence//xs:element[@name='address2']">
        <property>
          <baseType name="java.lang.String" />
        </property>
      </bindings>
      ...more fields
  </bindings>
</bindings>

When executing wsimport against the provided WSDL, StwrdCompany is generated with the following variables declared:

@XmlRootElement(name = "StwrdCompany")
public class StwrdCompany 
{
    @XmlElementRef(name = "company_name", type = JAXBElement.class)
    protected String companyName;
    @XmlElementRef(name = "address1", type = JAXBElement.class)
    protected String address1;
    @XmlElementRef(name = "address2", type = JAXBElement.class)
    ... more fields

    ... getters/setters

    @XmlAccessorType(XmlAccessType.FIELD)
    @XmlType(name = "", propOrder = {
        "value"
    })
    public static class CompanyName {

        @XmlValue
        protected String value;
        @XmlAttribute
        protected Boolean updateToNULL;

        /**
         * Gets the value of the value property.
         * 
         * @return
         *     possible object is
         *     {@link String }
         *     
         */
        public String getValue() {
            return value;
        }

        /**
         * Sets the value of the value property.
         * 
         * @param value
         *     allowed object is
         *     {@link String }
         *     
         */
        public void setValue(String value) {
            this.value = value;
        }

        /**
         * Gets the value of the updateToNULL property.
         * 
         * @return
         *     possible object is
         *     {@link Boolean }
         *     
         */
        public boolean isUpdateToNULL() {
            if (updateToNULL == null) {
                return false;
            } else {
                return updateToNULL;
            }
        }

        /**
         * Sets the value of the updateToNULL property.
         * 
         * @param value
         *     allowed object is
         *     {@link Boolean }
         *     
         */
        public void setUpdateToNULL(Boolean value) {
            this.updateToNULL = value;
        }

       ... more inner classes
       }
   }

Finally, here is the associated snippet from the WSDL that seems to be causing such grief.

<xs:element name="StwrdCompany">
  <xs:complexType>
    <xs:sequence>
      <xs:element maxOccurs="1" minOccurs="0" name="company_name" nillable="true">
        <xs:complexType>
          <xs:simpleContent>
            <xs:extension base="xs:string">
              <xs:attribute default="false" name="updateToNULL" type="xs:boolean"/>
            </xs:extension>
          </xs:simpleContent>
        </xs:complexType>
      </xs:element>
      <xs:element maxOccurs="1" minOccurs="0" name="address1" nillable="true">
        <xs:complexType>
          <xs:simpleContent>
            <xs:extension base="xs:string">
              <xs:attribute default="false" name="updateToNULL" type="xs:boolean"/>
            </xs:extension>
          </xs:simpleContent>
        </xs:complexType>
      </xs:element>
      ... more fields in the same format

      <xs:element maxOccurs="1" minOccurs="0" name="p_source_timestamp" nillable="false" type="xs:string"/>
    </xs:sequence>
    <xs:attribute name="company_xid" type="xs:string"/>
  </xs:complexType>
</xs:element>

The reason for the custom binding is so I can map user input from a pojo into the StwrdCompany object more easily, whether it be direct instantiation or through the use of Dozer for bean mapping. I was unable to successfully map between the objects without the custom binding.

Finally, one other thing I tried was setting a globalBinding definition:

<globalBindings generateValueClass="false"></globalBindings>  

This caused the server to through an argument mismatch exception since the Soap Message was using xs:string xml types instead of passing the defined complex types, so I abandoned that idea.

Any insight into what is causing the MarshalException or how to go about solving the issue of calling the webservice and mapping these objects more easily, is greatly appreciated. I've been searching for days and I sadly think I am stumped.

Answer 1

You need to add a <xjc:simple /> element inside your <jaxb:globalBindings> section for making JAXB handling root elements correctly. Just insert the following into your bindings file

<jaxb:globalBindings>
   <xjc:simple />
</jaxb:globalBindings>

I have a JAXB mapping sample here you can use for inspiration.

Answer 2

Thanks for posting the sample Lars. I've been struggling with using the xjc:simple tag in a bindings file that includes both of the following:

Basically the 'catalog' element contains a sequence of various kinds of different complexType elements with different tag names and when xjc auto-creates the classes without the binding to rename the sequence it produces something like 'itemType1AndItemType2' etc for the list and the methods involving it. I want to change that list to something better like just "catalogItems".

If I comment out the xjc:simple part it works or if I comment out the sequence rename binding everything also works, but they both won't work together. Any ideas why this would be? The error I'm getting is:

[ERROR] compiler was unable to honor this property customization. It is attached to a wrong place, or its inconsistent with other bindings.

Answer 3

That error means JAXB is trying to marshall a String as if it were an XML element -- which it obviously isn't. So, for example marshalling "foo" as XML, when really it should be something like "foo". The reason it's doing this is because of the mapping... making an element to a String also has the same effect the other way: so it's trying to map the String to an element, which results in invalid XML.

Lars' solution with should work. The other thing you can do is map it to a (simple) custom class that JAXB can marshal. If you're brave, you can try messing around with JAXBElement too.