JAXB's @XmlAnyElement(lax=true) Explained

In a previous post I introduced how the @XmlAnyElement(lax=true) annotation could be used to create a very flexible mapping.  In this post I'll dig a bit deeper into how it relates to both the @XmlRootElement and @XmlElementDecl.

JAXB - Representing Null and Empty Collections

In this post I will cover how to differentiate between null and empty collections in the XML representation with JAXB (JSR-222).

Creating a Generic List Wrapper in JAXB

To marshal/unmarshal a list with a JAXB (JSR-222) implementation you need to create a wrapper object to hold the list. People find this onerous having to create multiple wrapper objects for this purpose.  Below I'll demonstrate that in reality you only need to create one. This post is based on an answer I gave on Stack Overflow.

Using JAXB With XSLT to Produce HTML

JAXB (JSR-222) enables Java to treat a domain model as XML.  In this post I will demonstrate how to leverage this by applying an XSLT stylesheet to a JAXB model to produce HTML.  This approach is often leveraged when creating JAX-RS applications.

Applying a Namespace During JAXB Unmarshal

For some an XML schema is a strict set of rules for how the XML document must be structured.  But for others it is a general guideline to indicate what the XML should look like.  This means that sometimes people want to accept input that doesn't conform to the XML schema for some reason.  In this example I will demonstrate how this can be done by leveraging a SAX XMLFilter.

Updating EclipseLink in WebLogic

JSON binding was added to EclipseLink in version 2.4.  If you are using a version of that does not contain this version (i.e. WebLogic 10.3.4 (11g) contains EclipseLink 2.1.2), then by default you won't have access to this functionality. The recommended solution to this problem is to create a shared library in WebLogic for the newer release of EclipseLink.

Removing JAXBElement From Your Domain Model

JAXBElement is a JAXB (JSR-222) mechanism that stores name and namespace information in situations where this can not be determined from the value or mapping.  For example in the class below the elements billing-address and shipping-address both correspond to the Address class.  In order to be able to round trip the data we need to keep track of which element we unmarshalled.

import javax.xml.bind.JAXBElement;
import javax.xml.bind.annotation.*;

@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
public class Customer {

    @XmlElementRefs({
        @XmlElementRef(name = "billing-address"),
        @XmlElementRef(name = "shipping-address")
    })
    private JAXBElement<Address> address;

}

While useful JAXBElement can get in the way if you want to use your domain model with something like JPA (which doesn't know what to do with it).  In this post I will demonstrate how you can eliminate the need for JAXBElement through the use of an XmlAdapter.

Handle the Middle of a XML Document with JAXB and StAX

Recently I have come across a lot of people asking how to read data from, or write data to the middle of an XML document.  In this post I will demonstrate how this can be done using JAXB with StAX.  Note:  JAXB (JSR-222) and StAX (JSR-173) implementations are included in the JDK/JRE since Java SE 6.

JAXB's @XmlTransient and Property Order

In previous articles I wrote about how the @XmlTransient annotation can be used at the type level to have a class excluded from the inheritance hierarchy, or at the field/property level to unmap a field/property.  In this article I'll demonstrate how doing this impacts the propOrder setting on the @XmlType annotation.

JAXB and Root Elements

@XmlRootElement is an annotation that people are used to using with JAXB (JSR-222).  It's purpose is to uniquely associate a root element with a class.  Since JAXB classes map to complex types, it is possible for a class to correspond to multiple root elements. In this case @XmlRootElement can not be used and people start getting a bit confused.  In this post I'll demonstrate how @XmlElementDecl can be used to map this use case.