Reduce code duplication in JAXB-generated classes from two very similar (but different) schemas

Question

I have a (very large) XML schema with the namespace myschema_1.0. Recently, this schema was updated with some minimal but significant changes, resulting in a new version with the namespace myschema_1.1.

My application needs to support both versions, so I've generated Java classes for each. JAXB places them in separate packages, but since most definitions are identical, this results in a lot of code duplication in both the generated files and the application logic.

• Generated Files: Since most definitions between the two schema versions are identical, many classes are almost exact copies of each other.
• Application Code: Every operation that interacts with these classes must be implemented separately for each version, leading to redundant code.

Constraints and attempts

• Schema files cannot be changed.
• I've tried using JAXB bindings to define common interfaces, but this requires manually creating interfaces for thousands of elements.
• I also considered using custom JAXB adapters to handle conversions between old and new classes, but this also demands extensive manual coding.

Simple Example

Consider the following simplified example:

Schema Version 1.0 (myschema_1.0.xsd):

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" targetNamespace="myschema_1.0">
    <xs:element name="Person">
        <xs:complexType>
            <xs:sequence>
                <xs:element name="FirstName" type="xs:string"/>
                <xs:element name="LastName" type="xs:string"/>
            </xs:sequence>
        </xs:complexType>
    </xs:element>
</xs:schema>

Schema Version 1.1 (myschema_1.1.xsd):

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" targetNamespace="myschema_1.1">
    <xs:element name="Person">
        <xs:complexType>
            <xs:sequence>
                <xs:element name="FirstName" type="xs:string"/>
                <xs:element name="LastName" type="xs:string"/>
                <xs:element name="MiddleName" type="xs:string" minOccurs="0"/>
            </xs:sequence>
        </xs:complexType>
    </xs:element>
</xs:schema>

For these schemas, JAXB generates the following classes in separate packages:

• com.example.myschema_1_0.Person
• com.example.myschema_1_1.Person

Although the Person class in myschema_1.0 and myschema_1.1 are almost identical, except for the optional MiddleName field, any code that works with the Person object needs to handle both versions separately.

The Question

Is there a way to automatically extract common definitions or create shared interfaces without manually writing thousands of adapters or interfaces? I've thought about using tools like Schematron or XMLSpy to identify common elements, but I’m unsure how to integrate them into my JAXB workflow.

Given that I cannot change the schema files, how can I effectively reduce this duplication?