Handling XML Namespaces in Java's JAXB When Unmarshalling Nested Elements
I'm working on a Java application that uses JAXB for XML processing. I need to unmarshal an XML document that contains nested elements with different namespaces. The XML looks like this: ```xml <root xmlns:ns1="http://example.com/ns1" xmlns:ns2="http://example.com/ns2"> <ns1:item> <ns1:name>Item 1</ns1:name> <ns2:details> <ns2:description>This is a description.</ns2:description> </ns2:details> </ns1:item> </root> ``` I have created the following JAXB classes including the necessary annotations: ```java @XmlRootElement(name = "root") @XmlAccessorType(XmlAccessType.FIELD) public class Root { @XmlElement(name = "item", namespace = "http://example.com/ns1") private Item item; // getters and setters } @XmlAccessorType(XmlAccessType.FIELD) public class Item { @XmlElement(name = "name", namespace = "http://example.com/ns1") private String name; @XmlElement(name = "details", namespace = "http://example.com/ns1") private Details details; // getters and setters } @XmlAccessorType(XmlAccessType.FIELD) public class Details { @XmlElement(name = "description", namespace = "http://example.com/ns2") private String description; // getters and setters } ``` However, when I attempt to unmarshal the XML using the following code: ```java JAXBContext jaxbContext = JAXBContext.newInstance(Root.class); Unmarshaller unmarshaller = jaxbContext.createUnmarshaller(); Root root = (Root) unmarshaller.unmarshal(new File("path/to/file.xml")); ``` I encounter the following exception: ``` javax.xml.bind.UnmarshalException: unexpected element (uri:"http://example.com/ns2", local:"details") ``` It appears that JAXB is unable to recognize the nested `details` element due to the namespace mismatch. I tried adding the namespace to the `Item` class, but it didn't resolve the issue. I've also ensured that the XML file is correctly formed and accessible. What steps should I take to successfully unmarshal this XML with the nested elements using JAXB? Do I need to adjust the namespaces in my annotations or perhaps modify my XML structure?