For elements with multiplicity > 1 (i.e.. where maxOccurs>1 or maxOccurs=unbound), e.g.:
<element name="Name" type="tns:Type" minOccurs="0" maxOccurs="unbound"/>
JAXB generates the following code:
@XmlElement(name = "Name")
protected List<type> name;
Strictly speaking the above schema describes an XML snippet that looks like so:
<Name attr1="a" attr2="x">
<Name attr1="b" attr2="y">
<Name attr1="c" attr2="z">
i.e. a sequence of "Name" elements (and only that!).
When marshalling a Java object to XML the JAXB runtime creates XML, which contains an additional wrapper element around the list, like so:
<Name>
<Name attr1="a" attr2="x">
<Name attr1="b" attr2="y">
<Name attr1="c" attr2="z">
<Name>
By default the wrapping element has the same name as the individual items. Note, that there is no Java class representing that element!
One can overrule the naming to something that makes more sense by manually (!) adding a java-annotation "@XmlElementWrapper" annotation, like so:
@XmlElementWrapper(name = "NameList")
@XmlElement(name = "Name")
protected List<Type> name;
which then yields the following XML:
<NameList>
<Name attr1="a" attr2="x">
<Name attr1="b" attr2="y">
<Name attr1="c" attr2="z">
<NameList>
I agree that such a wrapper element is syntactically nice and makes the XML more readable, BUT there is a severe problem with this: the generated Java code (with or without renaming the wrapper element) generates and expects an XML dialect which - strictly speaking - does not match the original schema anymore! There is no mentioning or any implicit notion of any such wrapper element in the original schema!
The issue only surfaces, if one uses the original schema in different tools (e.g. to create web forms or a different schema-based code generator) and if their result then adheres and/or expects the original XML (i.e. the bare sequence without any wrapper element), while the JAXB-generated code creates and insists on the presence of the wrapper element. Then the two cannot understand each other!
My question thus: how can one instruct JAXB to NOT add/expect said wrapper element while marshalling/unmarshalling XML?
I have searched the web now for quite a while for solutions or work-arounds to this but found nothing! I can't imagine that nobody else before ever stumbled over this and that there seems no other solution to this other problem than to hand-tweak the XML marshalling/unmarshalling code. Any ideas or suggestions to solve this issue?