JAXB (Java Architecture for XML Binding)

JAXB (Java Architecture for XML Binding) is a Java framework that allows Java developers to map Java classes to XML representations. JAXB provides a convenient way to bind XML schemas and Java representations, making it easier to serialize Java objects into XML and deserialize XML back into Java objects.

It's a part of the Java SE platform and is commonly used in web services and applications that require XML processing.

JAXB simplifies the conversion process between Java objects and XML documents. This process is known as Object-XML mapping or OXM. The core operations of JAXB are marshalling (converting Java objects to XML) and unmarshalling (converting XML to Java objects).

JAXB uses Java annotations to define how Java classes are mapped to XML. For example, @XmlElement and @XmlAttribute are used to map Java fields to XML elements and attributes, respectively.

JAXB allows for the generation of Java classes from XML schemas (XSD) and vice versa, facilitating development in applications that rely on XML schemas. JAXB is often used in conjunction with JAX-RS (for RESTful web services) and JAX-WS (for SOAP web services) for data binding XML payloads.

In web services, JAXB is used to bind request and response payloads, which are typically in XML format, to their corresponding Java objects. Being a part of standard Java API, JAXB provides a portable way to work with XML across different Java applications.

Before JAXB, working with XML in Java was more complex, often involving low-level APIs like DOM (Document Object Model) or SAX (Simple API for XML). JAXB abstracts these complexities. While JAXB is part of Java SE, it is also widely used in Java EE applications, particularly those involving web services.

Other libraries like Jackson or XStream can also be used for XML binding in Java, offering different features and configurations.