Using JAXB in Java 9+

TL;DR

If you need to use JAXB in Java 9 or higher versions, add this dependency to your project and you are fine:

<dependency>
  <groupId>org.glassfish.jaxb</groupId>
  <artifactId>jaxb-runtime</artifactId>
  <version>2.3.0</version>
</dependency>

Slightly More Detailed Version

Starting with Java 9 some Java EE APIs that have been part of the Java platform for a long time have been deprecated and are likely to be removed in future Java releases. Java 9 encapsulates these APIs into modules which are marked as deprecated for removal. JEP 261 does specifically mention these modules for removal in future releases:

• java.activation
• java.corba
• java.transaction
• java.xml.bind
• java.xml.ws
• java.xml.ws.annotation

JEP 320, which is targeted for Java 11 (due in September 2018), proposes the effective removal of these modules.

This post focuses on the JAXB implementation which is currently used in many productive Java applications.

When migrating from Java 8 (or lower versions) to Java 9, such applications will neither compile nor run without taking further actions because the java.xml.bind module is not visible by default.

There are two possibilies to get such applications built and run with Java 9:

1. Explicitly add the java.xml.bind module at compile and at runtime
2. Add JAXB as external library to your application

Option 1) is simple. Just add --add-modules java.xml.bind as additional option to your javac and your java command line. However, as JEP 320 indicates, this will only work for Java 9 and 10. As of Java 11, the java.xml.bind module will most likely not be part of the Java platform anymore. So this solution will not be working quite soon.

Option 2) is adding a JAXB implementation as external library to your application. Up to version 10, the Java platform contains the JAXB reference implementation from the Glassfish project. Adding the reference implementation as external library will enable a smooth transition to Java versions beyond version 10. Unfortunately, “adding the JAXB reference implementation as external library” is not as easy as it sounds. The Glassfish project published quite a few JAXB libraries, some with the groupId com.sum.xml.bind and some with the groupId org.glassfish.jaxb. So which is the right one? The answer is:

<dependency>
  <groupId>org.glassfish.jaxb</groupId>
  <artifactId>jaxb-runtime</artifactId>
  <version>2.3.0</version>
</dependency>

This library is the reference implementation of the JAXB API which is defined in org.glassfish.jaxb:jaxb-core. When you are using a build tool like Maven jaxb-core will be resolved transitively through jaxb-runtime. Additionally, the jaxb-runtime library does also contain a Java Service Loader descriptor defining this reference implementation as JAXB provider. The libraries with the groupId com.sun.xml.bind are only published for legacy purposes and should not be used.

So, adding jaxb-runtime as external library to your application will add the JAXB reference implementation as external component instead of using the build-in implementation to your application. If you have strict compatibility requirements, use version 2.2.10 as Java 8 replacement and version 2.3.0 as Java 9+ replacement.