Unexpected NullPointerException When Parsing XML with Jackson - Missing Elements Scenario
I'm relatively new to this, so bear with me. I'm stuck on something that should probably be simple. I'm encountering a `NullPointerException` when trying to parse an XML document using Jackson's XML module in a Spring Boot application. The XML I'm working with can have optional child elements, and sometimes these elements are missing entirely. Here's a sample of the XML structure: ```xml <person> <name>John Doe</name> <age>30</age> <address> <street>Main St</street> </address> <phone /> </person> ``` The `phone` element is optional and might not always be present. I have a corresponding Java class defined as follows: ```java import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlProperty; public class Person { private String name; private Integer age; @JacksonXmlProperty(localName = "address") private Address address; private String phone; // Getters and Setters } ``` When I try to deserialize this XML into a `Person` object, if the `phone` element is missing, I receive a `NullPointerException` when accessing the `phone` field in my service that processes the `Person` object later on. Here’s the deserialization code I’m using: ```java import com.fasterxml.jackson.dataformat.xml.XmlMapper; public Person parsePersonFromXml(String xml) throws Exception { XmlMapper xmlMapper = new XmlMapper(); return xmlMapper.readValue(xml, Person.class); } ``` I've confirmed that the XML is well-formed, and the `NullPointerException` is thrown in a method that processes the `phone` field, which leads me to believe that the absence of the `phone` element is causing the serialization process to not initialize the field properly. I've tried adding default values in the `Person` class, but that didn't resolve the issue. I also considered using `Optional<String>` for the `phone` field, but that doesn't seem to work as expected in this context. Any insights on how to handle optional XML elements without running into `NullPointerException` issues? Am I missing something in the setup with Jackson, or is there a more reliable way to handle this scenario? My development environment is Ubuntu. For context: I'm using Java on Ubuntu 22.04. What's the best practice here? I'm developing on macOS with Java.